Add a generic scalb implementation

This is a preparatory patch to enable building a _Float128
variant to ease reuse when building a _Float128 variant to
alias this long double only symbol.

Notably, stubs are added where missing to the native _Float128
sysdep dir to prevent building these newly templated variants
created inside the build directories.

Also noteworthy are the changes around LIBM_SVID_COMPAT.  These
changes are not intuitive.  The templated version is only
enabled when !LIBM_SVID_COMPAT, and the compat version is
predicated entirely on LIBM_SVID_COMPAT.  Thus, exactly one is
stubbed out entirely when building.  The nldbl scalb compat
files are updated to account for this.

Likewise, fixup the reuse of m68k's e_scalb{f,l}.c to include
it's override of e_scalb.c.  Otherwise, the search path finds
the templated copy in the build directory.  This could be
futher simplified by providing an overridden template, but I
lack the hardware to verify.

1 files changed, 3 insertions, 1 deletions

diff --git a/sysdeps/ieee754/ldbl-opt/w_scalb_compat.c b/sysdeps/ieee754/ldbl-opt/w_scalb_compat.c
index f6d53a5ba5..56735e825e 100644
--- a/sysdeps/ieee754/ldbl-opt/w_scalb_compat.c
+++ b/sysdeps/ieee754/ldbl-opt/w_scalb_compat.c
@@ -1,5 +1,7 @@
 #include <math_ldbl_opt.h>
 #include <math/w_scalb_compat.c>
-#if LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)
+#if LIBM_SVID_COMPAT
+# if LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)
 compat_symbol (libm, __scalb, scalbl, GLIBC_2_0);
+# endif
 #endif