[gcc r14-5476] testsuite: tsan: add fallback overload for pthread_cond_clockwait

[gcc r14-5476] testsuite: tsan: add fallback overload for pthread_cond_clockwait

[Alexandre Oliva]

https://gcc.gnu.org/g:f5d94999ee6a7bd247c3d74959ebdd46334d7804

commit r14-5476-gf5d94999ee6a7bd247c3d74959ebdd46334d7804
Author: Alexandre Oliva <oliva@adacore.com>
Date:   Tue Nov 14 22:16:29 2023 -0300

    testsuite: tsan: add fallback overload for pthread_cond_clockwait
    
    LTS GNU/Linux distros from 2018, still in use, don't have
    pthread_cond_clockwait.  There's no trivial way to detect it so as to
    make the test conditional, but there's an easy enough way to silence
    the fail due to lack of the function in libc, and that has nothing to
    do with the false positive that this is testing against.
    
    
    for  gcc/testsuite/ChangeLog
    
            * g++.dg/tsan/pthread_cond_clockwait.C: Add fallback overload.

Diff:
---
 gcc/testsuite/g++.dg/tsan/pthread_cond_clockwait.C | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/gcc/testsuite/g++.dg/tsan/pthread_cond_clockwait.C b/gcc/testsuite/g++.dg/tsan/pthread_cond_clockwait.C
index 82d6a5c8329..b43f3ebf80e 100644
--- a/gcc/testsuite/g++.dg/tsan/pthread_cond_clockwait.C
+++ b/gcc/testsuite/g++.dg/tsan/pthread_cond_clockwait.C
@@ -4,6 +4,19 @@
 
 #include <pthread.h>
 
+// This overloaded version should only be selected on targets that
+// don't have a pthread_cond_clockwait in pthread.h, and it will wait
+// indefinitely for the cond_signal that, in this testcase, ought to
+// be delivered.
+static inline int
+pthread_cond_clockwait (pthread_cond_t *cv,
+			pthread_mutex_t *mtx,
+			__clockid_t,
+			void const /* struct timespec */ *)
+{
+  return pthread_cond_wait (cv, mtx);
+}		   
+
 pthread_cond_t cv;
 pthread_mutex_t mtx;