Define struct rusage in sys/wait.h when required (bug 21575).

Some older standards (XPG4.2 through POSIX.1:2001, XSI only) require
sys/wait.h to include the definition of struct rusage.  This is
missing in glibc.

This patch adds the required definition.  struct rusage is moved to a
new header bits/types/struct_rusage.h to avoid bringing in the whole
of sys/resource.h (although the standards in question do allow the
whole of sys/resource.h to be brought in).  In the five
bits/resource.h headers, the only variation between the definitions of
struct rusage is that the sysdeps/unix/sysv/linux version is prepared
for x32 (by having anonymous unions with __syscall_slong_t fields) and
the others are not.  Thus, this version is suitable for use
generically (everything other than x32 simply has __syscall_slong_t
the same as long int, so there are no API or ABI changes involved, and
anonymous unions are already a required language feature for glibc
headers elsewhere), and this patch uses it as a base for the single
implementation of bits/types/struct_rusage.h.

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

	[BZ #21575]
	* resource/bits/types/struct_rusage.h: New file.
	* include/bits/types/struct_rusage.h: Likewise.
	* bits/resource.h (struct rusage): Include
	<bits/types/struct_rusage.h> instead of defining here.
	* sysdeps/unix/sysv/linux/bits/resource.h (struct rusage):
	Likewise.
	* sysdeps/unix/sysv/linux/alpha/bits/resource.h (struct rusage):
	Likewise.
	* sysdeps/unix/sysv/linux/mips/bits/resource.h (struct rusage):
	Likewise.
	* sysdeps/unix/sysv/linux/sparc/bits/resource.h (struct rusage):
	Likewise.
	* resource/Makefile (headers): Add bits/types/struct_rusage.h.
	* posix/sys/wait.h [__USE_XOPEN_EXTENDED && !__USE_XOPEN2K8]:
	Include <bits/types/struct_rusage.h>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/bits/types/struct_rusage.h b/include/bits/types/struct_rusage.h
new file mode 100644
index 0000000000..ff048bbd76
--- /dev/null
+++ b/include/bits/types/struct_rusage.h
@@ -0,0 +1 @@
+#include <resource/bits/types/struct_rusage.h>