[glibc/google/grte/v5-2.27/master] Work around a ppc clang inlining bug

[glibc/google/grte/v5-2.27/master] Work around a ppc clang inlining bug

[Fangrui Song]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=96509a9dcec99892802cdf7ac16f9b5e51ffccde

commit 96509a9dcec99892802cdf7ac16f9b5e51ffccde
Author: Stan Shebs <stanshebs@google.com>
Date:   Tue Sep 25 07:48:20 2018 -0700

    Work around a ppc clang inlining bug

Diff:
---
 sysdeps/pthread/aio_misc.c         | 3 +++
 sysdeps/unix/sysv/linux/aio_misc.h | 8 +++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/sysdeps/pthread/aio_misc.c b/sysdeps/pthread/aio_misc.c
index fb13d6210b..8d4a25894c 100644
--- a/sysdeps/pthread/aio_misc.c
+++ b/sysdeps/pthread/aio_misc.c
@@ -27,6 +27,9 @@
 #include <sys/param.h>
 #include <sys/stat.h>
 #include <sys/time.h>
+#if defined __clang__ && defined __powerpc64__
+#define UGLY_INLINE_HACK
+#endif
 #include <aio_misc.h>
 
 #ifndef aio_create_helper_thread
diff --git a/sysdeps/unix/sysv/linux/aio_misc.h b/sysdeps/unix/sysv/linux/aio_misc.h
index 0d8aa45516..f463c8fca7 100644
--- a/sysdeps/unix/sysv/linux/aio_misc.h
+++ b/sysdeps/unix/sysv/linux/aio_misc.h
@@ -35,7 +35,13 @@ __aio_start_notify_thread (void)
   INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &ss, NULL, _NSIG / 8);
 }
 
-extern inline int
+extern
+/* clang fails to inline properly in one case, and then linking fails
+   because the function was discarded, so ensure it's kept.  */
+#ifndef UGLY_INLINE_HACK
+inline
+#endif
+int
 __aio_create_helper_thread (pthread_t *threadp, void *(*tf) (void *),
 			    void *arg)
 {