Fix more namespace issues in sys/ucontext.h (bug 21457).

Continuing the fixes for namespace issues in sys/ucontext.h, this
patch moves various symbols into the implementation namespace in the
absence of __USE_MISC.  As with previous changes, it is nonexhaustive,
just covering more straightforward cases.

Structure fields are generally changed to have a prefix __ in the
absence of __USE_MISC, via a macro __ctx (used without a space before
the open parenthesis, since the result is a single identifier).
Various macros such as NGREG also have leading __ added.  No changes
are made to structure tags (and thus to C++ name mangling), except
that in the (unused) file sysdeps/i386/sys/ucontext.h, structures
defined inside other structures as the type for a field have their
tags removed in the non-__USE_MISC case (those structure tags would
not in any case have been visible in C++, because in C++ the scope of
such a tag is limited to the containing structure).  No changes are
made to the contents of bits/sigcontext.h, or to whether it is
included.  Because of remaining namespace issues, this patch does not
yet fix the bug or allow any XFAILs to be removed.

Tested for x86_64 and x86, and with build-many-glibcs.py.

	[BZ #21457]
	* sysdeps/arm/sys/ucontext.h (NGREG): Rename to __NGREG and define
	NGREG to __NGREG if [__USE_MISC].
	(gregset_t): Define using __NGREG.
	(__ctx): New macro.
	(mcontext_t): Use __ctx in defining fields.
	* sysdeps/i386/sys/ucontext.h (NGREG): Rename to __NGREG and
	define NGREG to __NGREG if [__USE_MISC].
	(gregset_t): Define using __NGREG.
	(__ctx): New macro.
	(__ctxt): Likewise.
	(fpregset_t): Use __ctx and __ctxt in defining fields.
	(mcontext_t): Likewise.
	* sysdeps/m68k/sys/ucontext.h (NGREG): Rename to __NGREG and
	define NGREG to __NGREG if [__USE_MISC].
	(gregset_t): Define using __NGREG.
	(__ctx): New macro.
	(mcontext_t): Use __ctx in defining fields.
	* sysdeps/mips/sys/ucontext.h (NGREG): Rename to __NGREG and
	define NGREG to __NGREG if [__USE_MISC].
	(gregset_t): Define using __NGREG.
	(__ctx): New macro.
	(fpregset_t): Use __ctx in defining fields.
	(mcontext_t): Likewise.
	* sysdeps/unix/sysv/linux/alpha/sys/ucontext.h (NGREG): Rename to
	__NGREG and define NGREG to __NGREG if [__USE_MISC].
	(gregset_t): Define using __NGREG.
	(NFPREG): Rename to __NFPREG and define NFPREG to __NFPREG if
	[__USE_MISC].
	(fpregset_t): Define using __NFPREG.
	* sysdeps/unix/sysv/linux/m68k/sys/ucontext.h (NGREG): Rename to
	__NGREG and define NGREG to __NGREG if [__USE_MISC].
	(gregset_t): Define using __NGREG.
	(__ctx): New macro.
	(fpregset_t): Use __ctx in defining fields.
	(mcontext_t): Likewise.
	* sysdeps/unix/sysv/linux/mips/sys/ucontext.h (NGREG): Rename to
	__NGREG and define NGREG to __NGREG if [__USE_MISC].
	(NFPREG): Rename to __NFPREG and define NFPREG to __NFPREG if
	[__USE_MISC].
	(gregset_t): Define using __NGREG.
	(__ctx): New macro.
	(fpregset_t): Use __ctx in defining fields.
	(mcontext_t): Likewise.
	* sysdeps/unix/sysv/linux/nios2/sys/ucontext.h (__ctx): New macro.
	(mcontext_t): Use __ctx in defining fields.
	* sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h (__ctx): New
	macro.
	[__WORDSIZE == 32] (NGREG): Rename to __NGREG and define NGREG to
	__NGREG if [__USE_MISC].
	[__WORDSIZE == 32] (gregset_t): Define using __NGREG.
	[__WORDSIZE == 32] (fpregset_t): Use __ctx in defining fields.
	(mcontext_t): Likewise.
	[__WORDSIZE != 32] (NGREG): Rename to __NGREG and define NGREG to
	__NGREG if [__USE_MISC].
	[__WORDSIZE != 32] (NFPREG): Rename to __NFPREG and define NFPREG
	to __NFPREG if [__USE_MISC].
	[__WORDSIZE != 32] (NVRREG): Rename to __NVRREG and define NVRREG
	to __NVRREG if [__USE_MISC].
	[__WORDSIZE != 32] (gregset_t): Define using __NGREG.
	[__WORDSIZE != 32] (fpregset_t): Define using __NFPREG.
	[__WORDSIZE != 32] (vscr_t): Use __ctx in defining fields.
	[__WORDSIZE != 32] (vrregset_t): Likewise.
	[__WORDSIZE != 32] (mcontext_t): Likewise.
	* sysdeps/unix/sysv/linux/s390/sys/ucontext.h (__ctx): New macro.
	(__psw_t): Use __ctx in defining fields.
	(NGREG): Rename to __NGREG and define NGREG to __NGREG if
	[__USE_MISC].
	(gregset_t): Define using __NGREG.
	(fpreg_t): Use __ctx in defining fields.
	(fpregset_t): Likewise.
	(mcontext_t): Likewise.
	* sysdeps/unix/sysv/linux/sh/sys/ucontext.h (NGREG): Rename to
	__NGREG and define NGREG to __NGREG if [__USE_MISC].
	(gregset_t): Define using __NGREG.
	(NFPREG): Rename to __NFPREG and define NFPREG to __NFPREG if
	[__USE_MISC].
	(fpregset_t): Define using __NFPREG.
	(__ctx): New macro.
	(mcontext_t): Use __ctx in defining fields.
	* sysdeps/unix/sysv/linux/x86/sys/ucontext.h (__ctx): New macro.
	[__x86_64__] (NGREG): Rename to __NGREG and define NGREG to
	__NGREG if [__USE_MISC].
	[__x86_64__] (gregset_t): Define using __NGREG.
	[__x86_64__] (struct _libc_fpxreg): Use __ctx in defining fields.
	[__x86_64__] (struct _libc_fpstate): Likewise.
	[__x86_64__] (mcontext_t): Likewise.
	[!__x86_64__] (NGREG): Rename to __NGREG and define NGREG to
	__NGREG if [__USE_MISC].
	[!__x86_64__] (gregset_t): Define using __NGREG.
	[!__x86_64__] (struct _libc_fpreg): Use __ctx in defining fields.
	[!__x86_64__] (struct _libc_fpstate): Likewise.
	[!__x86_64__] (mcontext_t): Likewise.

13 files changed, 414 insertions, 178 deletions

diff --git a/ChangeLog b/ChangeLog
index d0bed8aa24..d56331a06d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,99 @@
+2017-06-01  Joseph Myers  <joseph@codesourcery.com>
+
+	[BZ #21457]
+	* sysdeps/arm/sys/ucontext.h (NGREG): Rename to __NGREG and define
+	NGREG to __NGREG if [__USE_MISC].
+	(gregset_t): Define using __NGREG.
+	(__ctx): New macro.
+	(mcontext_t): Use __ctx in defining fields.
+	* sysdeps/i386/sys/ucontext.h (NGREG): Rename to __NGREG and
+	define NGREG to __NGREG if [__USE_MISC].
+	(gregset_t): Define using __NGREG.
+	(__ctx): New macro.
+	(__ctxt): Likewise.
+	(fpregset_t): Use __ctx and __ctxt in defining fields.
+	(mcontext_t): Likewise.
+	* sysdeps/m68k/sys/ucontext.h (NGREG): Rename to __NGREG and
+	define NGREG to __NGREG if [__USE_MISC].
+	(gregset_t): Define using __NGREG.
+	(__ctx): New macro.
+	(mcontext_t): Use __ctx in defining fields.
+	* sysdeps/mips/sys/ucontext.h (NGREG): Rename to __NGREG and
+	define NGREG to __NGREG if [__USE_MISC].
+	(gregset_t): Define using __NGREG.
+	(__ctx): New macro.
+	(fpregset_t): Use __ctx in defining fields.
+	(mcontext_t): Likewise.
+	* sysdeps/unix/sysv/linux/alpha/sys/ucontext.h (NGREG): Rename to
+	__NGREG and define NGREG to __NGREG if [__USE_MISC].
+	(gregset_t): Define using __NGREG.
+	(NFPREG): Rename to __NFPREG and define NFPREG to __NFPREG if
+	[__USE_MISC].
+	(fpregset_t): Define using __NFPREG.
+	* sysdeps/unix/sysv/linux/m68k/sys/ucontext.h (NGREG): Rename to
+	__NGREG and define NGREG to __NGREG if [__USE_MISC].
+	(gregset_t): Define using __NGREG.
+	(__ctx): New macro.
+	(fpregset_t): Use __ctx in defining fields.
+	(mcontext_t): Likewise.
+	* sysdeps/unix/sysv/linux/mips/sys/ucontext.h (NGREG): Rename to
+	__NGREG and define NGREG to __NGREG if [__USE_MISC].
+	(NFPREG): Rename to __NFPREG and define NFPREG to __NFPREG if
+	[__USE_MISC].
+	(gregset_t): Define using __NGREG.
+	(__ctx): New macro.
+	(fpregset_t): Use __ctx in defining fields.
+	(mcontext_t): Likewise.
+	* sysdeps/unix/sysv/linux/nios2/sys/ucontext.h (__ctx): New macro.
+	(mcontext_t): Use __ctx in defining fields.
+	* sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h (__ctx): New
+	macro.
+	[__WORDSIZE == 32] (NGREG): Rename to __NGREG and define NGREG to
+	__NGREG if [__USE_MISC].
+	[__WORDSIZE == 32] (gregset_t): Define using __NGREG.
+	[__WORDSIZE == 32] (fpregset_t): Use __ctx in defining fields.
+	(mcontext_t): Likewise.
+	[__WORDSIZE != 32] (NGREG): Rename to __NGREG and define NGREG to
+	__NGREG if [__USE_MISC].
+	[__WORDSIZE != 32] (NFPREG): Rename to __NFPREG and define NFPREG
+	to __NFPREG if [__USE_MISC].
+	[__WORDSIZE != 32] (NVRREG): Rename to __NVRREG and define NVRREG
+	to __NVRREG if [__USE_MISC].
+	[__WORDSIZE != 32] (gregset_t): Define using __NGREG.
+	[__WORDSIZE != 32] (fpregset_t): Define using __NFPREG.
+	[__WORDSIZE != 32] (vscr_t): Use __ctx in defining fields.
+	[__WORDSIZE != 32] (vrregset_t): Likewise.
+	[__WORDSIZE != 32] (mcontext_t): Likewise.
+	* sysdeps/unix/sysv/linux/s390/sys/ucontext.h (__ctx): New macro.
+	(__psw_t): Use __ctx in defining fields.
+	(NGREG): Rename to __NGREG and define NGREG to __NGREG if
+	[__USE_MISC].
+	(gregset_t): Define using __NGREG.
+	(fpreg_t): Use __ctx in defining fields.
+	(fpregset_t): Likewise.
+	(mcontext_t): Likewise.
+	* sysdeps/unix/sysv/linux/sh/sys/ucontext.h (NGREG): Rename to
+	__NGREG and define NGREG to __NGREG if [__USE_MISC].
+	(gregset_t): Define using __NGREG.
+	(NFPREG): Rename to __NFPREG and define NFPREG to __NFPREG if
+	[__USE_MISC].
+	(fpregset_t): Define using __NFPREG.
+	(__ctx): New macro.
+	(mcontext_t): Use __ctx in defining fields.
+	* sysdeps/unix/sysv/linux/x86/sys/ucontext.h (__ctx): New macro.
+	[__x86_64__] (NGREG): Rename to __NGREG and define NGREG to
+	__NGREG if [__USE_MISC].
+	[__x86_64__] (gregset_t): Define using __NGREG.
+	[__x86_64__] (struct _libc_fpxreg): Use __ctx in defining fields.
+	[__x86_64__] (struct _libc_fpstate): Likewise.
+	[__x86_64__] (mcontext_t): Likewise.
+	[!__x86_64__] (NGREG): Rename to __NGREG and define NGREG to
+	__NGREG if [__USE_MISC].
+	[!__x86_64__] (gregset_t): Define using __NGREG.
+	[!__x86_64__] (struct _libc_fpreg): Use __ctx in defining fields.
+	[!__x86_64__] (struct _libc_fpstate): Likewise.
+	[!__x86_64__] (mcontext_t): Likewise.
+
 2017-06-01  Zack Weinberg  <zackw@panix.com>
 
 	* sysdeps/unix/sysv/linux/microblaze/pt-vfork.S: Don't include
diff --git a/sysdeps/arm/sys/ucontext.h b/sysdeps/arm/sys/ucontext.h
index 37277f0811..722300a7f1 100644
--- a/sysdeps/arm/sys/ucontext.h
+++ b/sysdeps/arm/sys/ucontext.h
@@ -30,10 +30,13 @@
 typedef int greg_t;
 
 /* Number of general registers.  */
-#define NGREG	16
+#define __NGREG	16
+#ifdef __USE_MISC
+# define NGREG	__NGREG
+#endif
 
 /* Container for all general registers.  */
-typedef greg_t gregset_t[NGREG];
+typedef greg_t gregset_t[__NGREG];
 
 #ifdef __USE_MISC
 /* Number of each register is the `gregset_t' array.  */
@@ -74,6 +77,12 @@ enum
 };
 #endif
 
+#ifdef __USE_MISC
+# define __ctx(fld) fld
+#else
+# define __ctx(fld) __ ## fld
+#endif
+
 /* Structure to describe FPU registers.  */
 typedef struct fpregset
   {
@@ -82,10 +91,12 @@ typedef struct fpregset
 /* Context to describe whole processor state.  */
 typedef struct
   {
-    gregset_t gregs;
-    fpregset_t fpregs;
+    gregset_t __ctx(gregs);
+    fpregset_t __ctx(fpregs);
   } mcontext_t;
 
+#undef __ctx
+
 /* Userlevel context.  */
 typedef struct ucontext
   {
diff --git a/sysdeps/i386/sys/ucontext.h b/sysdeps/i386/sys/ucontext.h
index a6b936a4c8..fb5df11965 100644
--- a/sysdeps/i386/sys/ucontext.h
+++ b/sysdeps/i386/sys/ucontext.h
@@ -31,10 +31,13 @@
 typedef int greg_t;
 
 /* Number of general registers.  */
-#define NGREG	19
+#define __NGREG	19
+#ifdef __USE_MISC
+# define NGREG	__NGREG
+#endif
 
 /* Container for all general registers.  */
-typedef greg_t gregset_t[NGREG];
+typedef greg_t gregset_t[__NGREG];
 
 #ifdef __USE_MISC
 /* Number of each register is the `gregset_t' array.  */
@@ -81,36 +84,47 @@ enum
 };
 #endif
 
+#ifdef __USE_MISC
+# define __ctx(fld) fld
+# define __ctxt(tag) tag
+#else
+# define __ctx(fld) __ ## fld
+# define __ctxt(tag) /* Empty.  */
+#endif
+
 /* Structure to describe FPU registers.  */
 typedef struct fpregset
   {
     union
       {
-	struct fpchip_state
+	struct __ctxt(fpchip_state)
 	  {
-	    int state[27];
-	    int status;
-	  } fpchip_state;
+	    int __ctx(state)[27];
+	    int __ctx(status);
+	  } __ctx(fpchip_state);
 
-	struct fp_emul_space
+	struct __ctxt(fp_emul_space)
 	  {
-	    char fp_emul[246];
-	    char fp_epad[2];
-	  } fp_emul_space;
+	    char __ctx(fp_emul)[246];
+	    char __ctx(fp_epad)[2];
+	  } __ctx(fp_emul_space);
 
-	int f_fpregs[62];
-      } fp_reg_set;
+	int __ctx(f_fpregs)[62];
+      } __ctx(fp_reg_set);
 
-    long int f_wregs[33];
+    long int __ctx(f_wregs)[33];
   } fpregset_t;
 
 /* Context to describe whole processor state.  */
 typedef struct
   {
-    gregset_t gregs;
-    fpregset_t fpregs;
+    gregset_t __ctx(gregs);
+    fpregset_t __ctx(fpregs);
   } mcontext_t;
 
+#undef __ctx
+#undef __ctxt
+
 /* Userlevel context.  */
 typedef struct ucontext
   {
diff --git a/sysdeps/m68k/sys/ucontext.h b/sysdeps/m68k/sys/ucontext.h
index 2b70e72fc4..a742aaff9a 100644
--- a/sysdeps/m68k/sys/ucontext.h
+++ b/sysdeps/m68k/sys/ucontext.h
@@ -31,10 +31,13 @@
 typedef int greg_t;
 
 /* Number of general registers.  */
-#define NGREG	18
+#define __NGREG	18
+#ifdef __USE_MISC
+# define NGREG	__NGREG
+#endif
 
 /* Container for all general registers.  */
-typedef greg_t gregset_t[NGREG];
+typedef greg_t gregset_t[__NGREG];
 
 #ifdef __USE_MISC
 /* Number of each register is the `gregset_t' array.  */
@@ -90,13 +93,21 @@ typedef struct fpregset
 } fpregset_t;
 #endif
 
+#ifdef __USE_MISC
+# define __ctx(fld) fld
+#else
+# define __ctx(fld) __ ## fld
+#endif
+
 /* Context to describe whole processor state.  */
 typedef struct
 {
-  int version;
-  gregset_t gregs;
+  int __ctx(version);
+  gregset_t __ctx(gregs);
 } mcontext_t;
 
+#undef __ctx
+
 #ifdef __USE_MISC
 # define MCONTEXT_VERSION 1
 #endif
diff --git a/sysdeps/mips/sys/ucontext.h b/sysdeps/mips/sys/ucontext.h
index ebc06099ac..4bc1bc199a 100644
--- a/sysdeps/mips/sys/ucontext.h
+++ b/sysdeps/mips/sys/ucontext.h
@@ -37,10 +37,13 @@ typedef __uint64_t greg_t;
 #endif
 
 /* Number of general registers.  */
-#define NGREG	36
+#define __NGREG	36
+#ifdef __USE_MISC
+# define NGREG	__NGREG
+#endif
 
 /* Container for all general registers.  */
-typedef greg_t gregset_t[NGREG];
+typedef greg_t gregset_t[__NGREG];
 
 #ifdef __USE_MISC
 /* Number of each register is the `gregset_t' array.  */
@@ -121,32 +124,40 @@ enum
 };
 #endif
 
+#ifdef __USE_MISC
+# define __ctx(fld) fld
+#else
+# define __ctx(fld) __ ## fld
+#endif
+
 /* Structure to describe FPU registers.  */
 typedef struct fpregset
 {
   union
   {
 #if _MIPS_SIM == _ABIO32
-    double fp_dregs[16];
-    float fp_fregs[32];
-    unsigned int fp_regs[32];
+    double __ctx(fp_dregs)[16];
+    float __ctx(fp_fregs)[32];
+    unsigned int __ctx(fp_regs)[32];
 #else
-    double fp_dregs[32];
-    /* float fp_fregs[32]; */
-    __uint64_t fp_regs[32];
+    double __ctx(fp_dregs)[32];
+    /* float __ctx(fp_fregs)[32]; */
+    __uint64_t __ctx(fp_regs)[32];
 #endif
-  } fp_r;
-  unsigned int fp_csr;
-  unsigned int fp_pad;
+  } __ctx(fp_r);
+  unsigned int __ctx(fp_csr);
+  unsigned int __ctx(fp_pad);
 } fpregset_t;
 
 /* Context to describe whole processor state.  */
 typedef struct
 {
-  gregset_t gpregs;
-  fpregset_t fpregs;
+  gregset_t __ctx(gpregs);
+  fpregset_t __ctx(fpregs);
 } mcontext_t;
 
+#undef __ctx
+
 /* Userlevel context.  */
 typedef struct ucontext
 {
diff --git a/sysdeps/unix/sysv/linux/alpha/sys/ucontext.h b/sysdeps/unix/sysv/linux/alpha/sys/ucontext.h
index 09e24a1f85..b9e590347e 100644
--- a/sysdeps/unix/sysv/linux/alpha/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/alpha/sys/ucontext.h
@@ -29,19 +29,25 @@
 typedef long int greg_t;
 
 /* Number of general registers.  */
-#define NGREG	33
+#define __NGREG	33
+#ifdef __USE_MISC
+# define NGREG	__NGREG
+#endif
 
 /* Container for all general registers.  */
-typedef greg_t gregset_t[NGREG];
+typedef greg_t gregset_t[__NGREG];
 
 /* Type for floating-point register.  */
 typedef long int fpreg_t;
 
 /* Number of general registers.  */
-#define NFPREG	32
+#define __NFPREG	32
+#ifdef __USE_MISC
+# define NFPREG	__NFPREG
+#endif
 
 /* Container for all general registers.  */
-typedef fpreg_t fpregset_t[NFPREG];
+typedef fpreg_t fpregset_t[__NFPREG];
 
 
 /* A machine context is exactly a sigcontext.  */
diff --git a/sysdeps/unix/sysv/linux/m68k/sys/ucontext.h b/sysdeps/unix/sysv/linux/m68k/sys/ucontext.h
index 0570ec3c3d..e6ecbe6ab5 100644
--- a/sysdeps/unix/sysv/linux/m68k/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/m68k/sys/ucontext.h
@@ -31,10 +31,13 @@
 typedef int greg_t;
 
 /* Number of general registers.  */
-#define NGREG	18
+#define __NGREG	18
+#ifdef __USE_MISC
+# define NGREG	__NGREG
+#endif
 
 /* Container for all general registers.  */
-typedef greg_t gregset_t[NGREG];
+typedef greg_t gregset_t[__NGREG];
 
 #ifdef __USE_MISC
 /* Number of each register is the `gregset_t' array.  */
@@ -81,27 +84,35 @@ enum
 };
 #endif
 
+#ifdef __USE_MISC
+# define __ctx(fld) fld
+#else
+# define __ctx(fld) __ ## fld
+#endif
+
 /* Structure to describe FPU registers.  */
 typedef struct fpregset
 {
-  int f_pcr;
-  int f_psr;
-  int f_fpiaddr;
+  int __ctx(f_pcr);
+  int __ctx(f_psr);
+  int __ctx(f_fpiaddr);
 #ifdef __mcoldfire__
-  int f_fpregs[8][2];
+  int __ctx(f_fpregs)[8][2];
 #else
-  int f_fpregs[8][3];
+  int __ctx(f_fpregs)[8][3];
 #endif
 } fpregset_t;
 
 /* Context to describe whole processor state.  */
 typedef struct
 {
-  int version;
-  gregset_t gregs;
-  fpregset_t fpregs;
+  int __ctx(version);
+  gregset_t __ctx(gregs);
+  fpregset_t __ctx(fpregs);
 } mcontext_t;
 
+#undef __ctx
+
 #ifdef __USE_MISC
 # define MCONTEXT_VERSION 2
 #endif
diff --git a/sysdeps/unix/sysv/linux/mips/sys/ucontext.h b/sysdeps/unix/sysv/linux/mips/sys/ucontext.h
index d15d85dc64..048e9a46b7 100644
--- a/sysdeps/unix/sysv/linux/mips/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/mips/sys/ucontext.h
@@ -33,21 +33,31 @@
 __extension__ typedef unsigned long long int greg_t;
 
 /* Number of general registers.  */
-#define NGREG	32
-#define NFPREG	32
+#define __NGREG	32
+#define __NFPREG	32
+#ifdef __USE_MISC
+# define NGREG	__NGREG
+# define NFPREG	__NFPREG
+#endif
 
 /* Container for all general registers.  */
-typedef greg_t gregset_t[NGREG];
+typedef greg_t gregset_t[__NGREG];
+
+#ifdef __USE_MISC
+# define __ctx(fld) fld
+#else
+# define __ctx(fld) __ ## fld
+#endif
 
 /* Container for all FPU registers.  */
 typedef struct fpregset {
 	union {
-		double	fp_dregs[NFPREG];
+		double	__ctx(fp_dregs)[__NFPREG];
 		struct {
 			float		_fp_fregs;
 			unsigned int	_fp_pad;
-		} fp_fregs[NFPREG];
-	} fp_r;
+		} __ctx(fp_fregs)[__NFPREG];
+	} __ctx(fp_r);
 } fpregset_t;
 
 
@@ -60,46 +70,48 @@ typedef struct fpregset {
    still be rectified.  */
 typedef struct
   {
-    unsigned int regmask;
-    unsigned int status;
-    greg_t pc;
-    gregset_t gregs;
-    fpregset_t fpregs;
-    unsigned int fp_owned;
-    unsigned int fpc_csr;
-    unsigned int fpc_eir;
-    unsigned int used_math;
-    unsigned int dsp;
-    greg_t mdhi;
-    greg_t mdlo;
-    unsigned long hi1;
-    unsigned long lo1;
-    unsigned long hi2;
-    unsigned long lo2;
-    unsigned long hi3;
-    unsigned long lo3;
+    unsigned int __ctx(regmask);
+    unsigned int __ctx(status);
+    greg_t __ctx(pc);
+    gregset_t __ctx(gregs);
+    fpregset_t __ctx(fpregs);
+    unsigned int __ctx(fp_owned);
+    unsigned int __ctx(fpc_csr);
+    unsigned int __ctx(fpc_eir);
+    unsigned int __ctx(used_math);
+    unsigned int __ctx(dsp);
+    greg_t __ctx(mdhi);
+    greg_t __ctx(mdlo);
+    unsigned long __ctx(hi1);
+    unsigned long __ctx(lo1);
+    unsigned long __ctx(hi2);
+    unsigned long __ctx(lo2);
+    unsigned long __ctx(hi3);
+    unsigned long __ctx(lo3);
   } mcontext_t;
 #else
 typedef struct
   {
-    gregset_t gregs;
-    fpregset_t fpregs;
-    greg_t mdhi;
-    greg_t hi1;
-    greg_t hi2;
-    greg_t hi3;
-    greg_t mdlo;
-    greg_t lo1;
-    greg_t lo2;
-    greg_t lo3;
-    greg_t pc;
-    unsigned int fpc_csr;
-    unsigned int used_math;
-    unsigned int dsp;
+    gregset_t __ctx(gregs);
+    fpregset_t __ctx(fpregs);
+    greg_t __ctx(mdhi);
+    greg_t __ctx(hi1);
+    greg_t __ctx(hi2);
+    greg_t __ctx(hi3);
+    greg_t __ctx(mdlo);
+    greg_t __ctx(lo1);
+    greg_t __ctx(lo2);
+    greg_t __ctx(lo3);
+    greg_t __ctx(pc);
+    unsigned int __ctx(fpc_csr);
+    unsigned int __ctx(used_math);
+    unsigned int __ctx(dsp);
     unsigned int __glibc_reserved1;
   } mcontext_t;
 #endif
 
+#undef __ctx
+
 /* Userlevel context.  */
 typedef struct ucontext
   {
diff --git a/sysdeps/unix/sysv/linux/nios2/sys/ucontext.h b/sysdeps/unix/sysv/linux/nios2/sys/ucontext.h
index 72ae1a05c7..af8d75c435 100644
--- a/sysdeps/unix/sysv/linux/nios2/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/nios2/sys/ucontext.h
@@ -34,13 +34,21 @@
 # define MCONTEXT_VERSION 2
 #endif
 
+#ifdef __USE_MISC
+# define __ctx(fld) fld
+#else
+# define __ctx(fld) __ ## fld
+#endif
+
 /* Context to describe whole processor state.  */
 typedef struct mcontext
   {
-    int version;
-    unsigned long regs[32];
+    int __ctx(version);
+    unsigned long __ctx(regs)[32];
   } mcontext_t;
 
+#undef __ctx
+
 /* Userlevel context.  */
 typedef struct ucontext
   {
diff --git a/sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h b/sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h
index c10741cf53..b460f23bc9 100644
--- a/sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h
@@ -25,19 +25,28 @@
 #include <bits/types/stack_t.h>
 
 
+#ifdef __USE_MISC
+# define __ctx(fld) fld
+#else
+# define __ctx(fld) __ ## fld
+#endif
+
 #if __WORDSIZE == 32
 
 /* Number of general registers.  */
-# define NGREG	48
+# define __NGREG	48
+# ifdef __USE_MISC
+#  define NGREG	__NGREG
+# endif
 
 /* Container for all general registers.  */
-typedef unsigned long gregset_t[NGREG];
+typedef unsigned long gregset_t[__NGREG];
 
 /* Container for floating-point registers and status */
 typedef struct _libc_fpstate
 {
-	double fpregs[32];
-	double fpscr;
+	double __ctx(fpregs)[32];
+	double __ctx(fpscr);
 	unsigned int _pad[2];
 } fpregset_t;
 
@@ -45,18 +54,18 @@ typedef struct _libc_fpstate
    Needs to be aligned on a 16-byte boundary. */
 typedef struct _libc_vrstate
 {
-	unsigned int vrregs[32][4];
-	unsigned int vrsave;
+	unsigned int __ctx(vrregs)[32][4];
+	unsigned int __ctx(vrsave);
 	unsigned int _pad[2];
-	unsigned int vscr;
+	unsigned int __ctx(vscr);
 } vrregset_t;
 
 /* Context to describe whole processor state.  */
 typedef struct
 {
-	gregset_t gregs;
-	fpregset_t fpregs;
-	vrregset_t vrregs __attribute__((__aligned__(16)));
+	gregset_t __ctx(gregs);
+	fpregset_t __ctx(fpregs);
+	vrregset_t __ctx(vrregs) __attribute__((__aligned__(16)));
 } mcontext_t;
 
 #else
@@ -70,12 +79,18 @@ typedef struct
  * is set in AT_HWCAP.  */
 
 /* Number of general registers.  */
-# define NGREG	48	/* includes r0-r31, nip, msr, lr, etc.   */
-# define NFPREG	33	/* includes fp0-fp31 &fpscr.  */
-# define NVRREG	34	/* includes v0-v31, vscr, & vrsave in split vectors */
-
-typedef unsigned long gregset_t[NGREG];
-typedef double fpregset_t[NFPREG];
+# define __NGREG	48	/* includes r0-r31, nip, msr, lr, etc.   */
+# define __NFPREG	33	/* includes fp0-fp31 &fpscr.  */
+# define __NVRREG	34	/* includes v0-v31, vscr, & vrsave in
+				   split vectors */
+# ifdef __USE_MISC
+#  define NGREG	__NGREG
+#  define NFPREG	__NFPREG
+#  define NVRREG	__NVRREG
+# endif
+
+typedef unsigned long gregset_t[__NGREG];
+typedef double fpregset_t[__NFPREG];
 
 /* Container for Altivec/VMX Vector Status and Control Register.  Only 32-bits
    but can only be copied to/from a 128-bit vector register.  So we allocated
@@ -83,28 +98,28 @@ typedef double fpregset_t[NFPREG];
 typedef struct _libc_vscr
 {
 	unsigned int __pad[3];
-	unsigned int vscr_word;
+	unsigned int __ctx(vscr_word);
 } vscr_t;
 
 /* Container for Altivec/VMX registers and status.
    Must to be aligned on a 16-byte boundary. */
 typedef struct _libc_vrstate
 {
-	unsigned int	vrregs[32][4];
-	vscr_t		vscr;
-	unsigned int	vrsave;
+	unsigned int	__ctx(vrregs)[32][4];
+	vscr_t		__ctx(vscr);
+	unsigned int	__ctx(vrsave);
 	unsigned int	__pad[3];
 } vrregset_t  __attribute__((__aligned__(16)));
 
 typedef struct {
 	unsigned long	__glibc_reserved[4];
-	int		signal;
+	int		__ctx(signal);
 	int		__pad0;
-	unsigned long	handler;
-	unsigned long	oldmask;
-	struct pt_regs	*regs;
-	gregset_t	gp_regs;
-	fpregset_t	fp_regs;
+	unsigned long	__ctx(handler);
+	unsigned long	__ctx(oldmask);
+	struct pt_regs	*__ctx(regs);
+	gregset_t	__ctx(gp_regs);
+	fpregset_t	__ctx(fp_regs);
 /*
  * To maintain compatibility with current implementations the sigcontext is
  * extended by appending a pointer (v_regs) to a quadword type (elf_vrreg_t)
@@ -124,12 +139,14 @@ typedef struct {
  * The entry with index 33 contains the vrsave as the first word (offset 0)
  * within the quadword.
  */
-	vrregset_t	*v_regs;
-	long		vmx_reserve[NVRREG+NVRREG+1];
+	vrregset_t	*__ctx(v_regs);
+	long		__ctx(vmx_reserve)[__NVRREG+__NVRREG+1];
 } mcontext_t;
 
 #endif
 
+#undef __ctx
+
 /* Userlevel context.  */
 typedef struct ucontext
   {
diff --git a/sysdeps/unix/sysv/linux/s390/sys/ucontext.h b/sysdeps/unix/sysv/linux/s390/sys/ucontext.h
index 80410fa38c..183da5c8f9 100644
--- a/sysdeps/unix/sysv/linux/s390/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/s390/sys/ucontext.h
@@ -26,11 +26,17 @@
 #include <bits/types/stack_t.h>
 
 
+#ifdef __USE_MISC
+# define __ctx(fld) fld
+#else
+# define __ctx(fld) __ ## fld
+#endif
+
 /* Type for a program status word.  */
 typedef struct
 {
-  unsigned long mask;
-  unsigned long addr;
+  unsigned long __ctx(mask);
+  unsigned long __ctx(addr);
 } __attribute__ ((__aligned__(8))) __psw_t;
 
 /* Type for a general-purpose register.  */
@@ -42,35 +48,40 @@ typedef unsigned long greg_t;
    that has the same size as s390_regs.  This is needed for the
    elf_prstatus structure.  */
 #if __WORDSIZE == 64
-# define NGREG 27
+# define __NGREG 27
 #else
-# define NGREG 36
+# define __NGREG 36
+#endif
+#ifdef __USE_MISC
+# define NGREG __NGREG
 #endif
 /* Must match kernels psw_t alignment.  */
-typedef greg_t gregset_t[NGREG] __attribute__ ((__aligned__(8)));
+typedef greg_t gregset_t[__NGREG] __attribute__ ((__aligned__(8)));
 
 typedef union
   {
-    double  d;
-    float   f;
+    double  __ctx(d);
+    float   __ctx(f);
   } fpreg_t;
 
 /* Register set for the floating-point registers.  */
 typedef struct
   {
-    unsigned int fpc;
-    fpreg_t fprs[16];
+    unsigned int __ctx(fpc);
+    fpreg_t __ctx(fprs)[16];
   } fpregset_t;
 
 /* Context to describe whole processor state.  */
 typedef struct
   {
-    __psw_t psw;
-    unsigned long gregs[16];
-    unsigned int aregs[16];
-    fpregset_t fpregs;
+    __psw_t __ctx(psw);
+    unsigned long __ctx(gregs)[16];
+    unsigned int __ctx(aregs)[16];
+    fpregset_t __ctx(fpregs);
   } mcontext_t;
 
+#undef __ctx
+
 /* Userlevel context.  */
 typedef struct ucontext
   {
diff --git a/sysdeps/unix/sysv/linux/sh/sys/ucontext.h b/sysdeps/unix/sysv/linux/sh/sys/ucontext.h
index 7444298957..d44f95e0f9 100644
--- a/sysdeps/unix/sysv/linux/sh/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/sh/sys/ucontext.h
@@ -30,10 +30,13 @@
 typedef int greg_t;
 
 /* Number of general registers.  */
-#define NGREG	16
+#define __NGREG	16
+#ifdef __USE_MISC
+# define NGREG	__NGREG
+#endif
 
 /* Container for all general registers.  */
-typedef greg_t gregset_t[NGREG];
+typedef greg_t gregset_t[__NGREG];
 
 #ifdef __USE_MISC
 /* Number of each register is the `gregset_t' array.  */
@@ -77,29 +80,40 @@ enum
 typedef int freg_t;
 
 /* Number of FPU registers.  */
-#define NFPREG	16
+#define __NFPREG	16
+#ifdef __USE_MISC
+# define NFPREG	__NFPREG
+#endif
 
 /* Structure to describe FPU registers.  */
-typedef freg_t fpregset_t[NFPREG];
+typedef freg_t fpregset_t[__NFPREG];
+
+#ifdef __USE_MISC
+# define __ctx(fld) fld
+#else
+# define __ctx(fld) __ ## fld
+#endif
 
 /* Context to describe whole processor state.  */
 typedef struct
   {
-    unsigned int oldmask;
-    gregset_t gregs;
-    unsigned int pc;
-    unsigned int pr;
-    unsigned int sr;
-    unsigned int gbr;
-    unsigned int mach;
-    unsigned int macl;
-    fpregset_t fpregs;
-    fpregset_t xfpregs;
-    unsigned int fpscr;
-    unsigned int fpul;
-    unsigned int ownedfp;
+    unsigned int __ctx(oldmask);
+    gregset_t __ctx(gregs);
+    unsigned int __ctx(pc);
+    unsigned int __ctx(pr);
+    unsigned int __ctx(sr);
+    unsigned int __ctx(gbr);
+    unsigned int __ctx(mach);
+    unsigned int __ctx(macl);
+    fpregset_t __ctx(fpregs);
+    fpregset_t __ctx(xfpregs);
+    unsigned int __ctx(fpscr);
+    unsigned int __ctx(fpul);
+    unsigned int __ctx(ownedfp);
   } mcontext_t;
 
+#undef __ctx
+
 /* Userlevel context.  */
 typedef struct ucontext
   {
diff --git a/sysdeps/unix/sysv/linux/x86/sys/ucontext.h b/sysdeps/unix/sysv/linux/x86/sys/ucontext.h
index 92a698e4b4..5fd64bf801 100644
--- a/sysdeps/unix/sysv/linux/x86/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/x86/sys/ucontext.h
@@ -25,16 +25,25 @@
 #include <bits/types/stack_t.h>
 
 
+#ifdef __USE_MISC
+# define __ctx(fld) fld
+#else
+# define __ctx(fld) __ ## fld
+#endif
+
 #ifdef __x86_64__
 
 /* Type for general register.  */
 __extension__ typedef long long int greg_t;
 
 /* Number of general registers.  */
-#define NGREG	23
+#define __NGREG	23
+#ifdef __USE_MISC
+# define NGREG	__NGREG
+#endif
 
 /* Container for all general registers.  */
-typedef greg_t gregset_t[NGREG];
+typedef greg_t gregset_t[__NGREG];
 
 #ifdef __USE_GNU
 /* Number of each register in the `gregset_t' array.  */
@@ -91,8 +100,8 @@ enum
 
 struct _libc_fpxreg
 {
-  unsigned short int significand[4];
-  unsigned short int exponent;
+  unsigned short int __ctx(significand)[4];
+  unsigned short int __ctx(exponent);
   unsigned short int __glibc_reserved1[3];
 };
 
@@ -104,14 +113,14 @@ struct _libc_xmmreg
 struct _libc_fpstate
 {
   /* 64-bit FXSAVE format.  */
-  __uint16_t		cwd;
-  __uint16_t		swd;
-  __uint16_t		ftw;
-  __uint16_t		fop;
-  __uint64_t		rip;
-  __uint64_t		rdp;
-  __uint32_t		mxcsr;
-  __uint32_t		mxcr_mask;
+  __uint16_t		__ctx(cwd);
+  __uint16_t		__ctx(swd);
+  __uint16_t		__ctx(ftw);
+  __uint16_t		__ctx(fop);
+  __uint64_t		__ctx(rip);
+  __uint64_t		__ctx(rdp);
+  __uint32_t		__ctx(mxcsr);
+  __uint32_t		__ctx(mxcr_mask);
   struct _libc_fpxreg	_st[8];
   struct _libc_xmmreg	_xmm[16];
   __uint32_t		__glibc_reserved1[24];
@@ -123,9 +132,9 @@ typedef struct _libc_fpstate *fpregset_t;
 /* Context to describe whole processor state.  */
 typedef struct
   {
-    gregset_t gregs;
+    gregset_t __ctx(gregs);
     /* Note that fpregs is a pointer.  */
-    fpregset_t fpregs;
+    fpregset_t __ctx(fpregs);
     __extension__ unsigned long long __reserved1 [8];
 } mcontext_t;
 
@@ -146,10 +155,13 @@ typedef struct ucontext
 typedef int greg_t;
 
 /* Number of general registers.  */
-#define NGREG	19
+#define __NGREG	19
+#ifdef __USE_MISC
+# define NGREG	__NGREG
+#endif
 
 /* Container for all general registers.  */
-typedef greg_t gregset_t[NGREG];
+typedef greg_t gregset_t[__NGREG];
 
 #ifdef __USE_GNU
 /* Number of each register is the `gregset_t' array.  */
@@ -199,21 +211,21 @@ enum
 /* Definitions taken from the kernel headers.  */
 struct _libc_fpreg
 {
-  unsigned short int significand[4];
-  unsigned short int exponent;
+  unsigned short int __ctx(significand)[4];
+  unsigned short int __ctx(exponent);
 };
 
 struct _libc_fpstate
 {
-  unsigned long int cw;
-  unsigned long int sw;
-  unsigned long int tag;
-  unsigned long int ipoff;
-  unsigned long int cssel;
-  unsigned long int dataoff;
-  unsigned long int datasel;
+  unsigned long int __ctx(cw);
+  unsigned long int __ctx(sw);
+  unsigned long int __ctx(tag);
+  unsigned long int __ctx(ipoff);
+  unsigned long int __ctx(cssel);
+  unsigned long int __ctx(dataoff);
+  unsigned long int __ctx(datasel);
   struct _libc_fpreg _st[8];
-  unsigned long int status;
+  unsigned long int __ctx(status);
 };
 
 /* Structure to describe FPU registers.  */
@@ -222,12 +234,12 @@ typedef struct _libc_fpstate *fpregset_t;
 /* Context to describe whole processor state.  */
 typedef struct
   {
-    gregset_t gregs;
+    gregset_t __ctx(gregs);
     /* Due to Linux's history we have to use a pointer here.  The SysV/i386
        ABI requires a struct with the values.  */
-    fpregset_t fpregs;
-    unsigned long int oldmask;
-    unsigned long int cr2;
+    fpregset_t __ctx(fpregs);
+    unsigned long int __ctx(oldmask);
+    unsigned long int __ctx(cr2);
   } mcontext_t;
 
 /* Userlevel context.  */
@@ -243,4 +255,6 @@ typedef struct ucontext
 
 #endif /* !__x86_64__ */
 
+#undef __ctx
+
 #endif /* sys/ucontext.h */