Added configure test for pthread_yield() and sem_init().

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@11109 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/configure.in b/configure.in
index eb30cd0..f197fb7 100644
--- a/configure.in
+++ b/configure.in
@@ -1516,16 +1516,18 @@
         pthread_rwlock_timedrdlock \
         pthread_rwlock_timedwrlock \
         pthread_spin_lock          \
+        pthread_yield              \
         readlinkat   \
+        sem_init     \
         semtimedop   \
         signalfd     \
         sigwaitinfo  \
-        syscall      \
         strchr       \
         strdup       \
         strpbrk      \
         strrchr      \
         strstr       \
+        syscall      \
         timerfd      \
         utimensat    \
         ])