Simplify Linux sig{timed}wait{info} implementations

This patch simplifies sig{timed}wait{info} by:

  - Assuming __NR_rt_sigtimedwait existence on all architectures due minimum
    kernel version requirement (it pre-dates Linux git inclusion for Linux
    2.6.12).

  - Call __sigtimedwait on both sigwait and sigwaitinfo.

  - Now that sigwait is based on an internal sigtimedwait call and it is
    present of both libc.so and libpthread.so we need to add an external
    private definition of __sigtimedwait for libpthread.so call.

Checked on x86_64-linux-gnu.

	* sysdeps/unix/sysv/linux/Versions (libc) [GLIBC_PRIVATE]: Add
	__sigtimedwait.
	* sysdeps/unix/sysv/linux/sigtimedwait.c: Simplify includes and
	assume __NR_rt_sigtimedwait.
	* sysdeps/unix/sysv/linux/sigwait.c (__sigwait): Call __sigtimedwait
	and add LIBC_CANCEL_HANDLED for cancellation marking.
	* sysdeps/unix/sysv/linux/sigwaitinfo.c (__sigwaitinfo): Likewise.

Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Zack Weinberg <zackw@panix.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 7abc8f6f0f..89e0f11b70 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
 2017-11-06  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 
+	* sysdeps/unix/sysv/linux/Versions (libc) [GLIBC_PRIVATE]: Add
+	__sigtimedwait.
+	* sysdeps/unix/sysv/linux/sigtimedwait.c: Simplify includes and
+	assume __NR_rt_sigtimedwait.
+	* sysdeps/unix/sysv/linux/sigwait.c (__sigwait): Call __sigtimedwait
+	and add LIBC_CANCEL_HANDLED for cancellation marking.
+	* sysdeps/unix/sysv/linux/sigwaitinfo.c (__sigwaitinfo): Likewise.
+
 	* sysdeps/arm/armv7/multiarch/Makefile [$(subdir) = string]
 	(sysdeps_routines): Add memchr_noneon.
 	* sysdeps/arm/armv7/multiarch/ifunc-memchr.h: New file.