Check for sem_timedwait(), which isn't available on some systems (including OpenBSD

configure

@@ -24485,6 +24485,67 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
                 { echo "$as_me:$LINENO: result: $have_pthread_sem" >&5
 echo "${ECHO_T}$have_pthread_sem" >&6; }
             fi
+            if test x$have_pthread_sem = xyes; then
+                { echo "$as_me:$LINENO: checking for sem_timedwait" >&5
+echo $ECHO_N "checking for sem_timedwait... $ECHO_C" >&6; }
+                have_sem_timedwait=no
+                cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+                  #include <pthread.h>
+                  #include <semaphore.h>
+
+int
+main ()
+{
+
+                  sem_timedwait(NULL, NULL);
+
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest$ac_exeext &&
+       $as_test_x conftest$ac_exeext; then
+
+                have_sem_timedwait=yes
+                cat >>confdefs.h <<\_ACEOF
+#define HAVE_SEM_TIMEDWAIT 1
+_ACEOF
+
+
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
+      conftest$ac_exeext conftest.$ac_ext
+                { echo "$as_me:$LINENO: result: $have_sem_timedwait" >&5
+echo "${ECHO_T}$have_sem_timedwait" >&6; }
+            fi
 
             { echo "$as_me:$LINENO: checking for pthread_spin_trylock" >&5
 echo $ECHO_N "checking for pthread_spin_trylock... $ECHO_C" >&6; }

configure.in

@@ -1742,6 +1742,20 @@ AC_HELP_STRING([--enable-pthread-sem], [use pthread semaphores [[default=yes]]])
                 ])
                 AC_MSG_RESULT($have_pthread_sem)
             fi
+            if test x$have_pthread_sem = xyes; then
+                AC_MSG_CHECKING(for sem_timedwait)
+                have_sem_timedwait=no
+                AC_TRY_LINK([
+                  #include <pthread.h>
+                  #include <semaphore.h>
+                ],[
+                  sem_timedwait(NULL, NULL);
+                ],[
+                have_sem_timedwait=yes
+                AC_DEFINE(HAVE_SEM_TIMEDWAIT)
+                ])
+                AC_MSG_RESULT($have_sem_timedwait)
+            fi
 
             AC_MSG_CHECKING(for pthread_spin_trylock)
             AC_TRY_LINK_FUNC(pthread_spin_trylock, [

include/SDL_config_generated.h.in

@@ -151,6 +151,7 @@
 #undef HAVE_ICONV
 #undef HAVE_PTHREAD_SETNAME_NP
 #undef HAVE_PTHREAD_SET_NAME_NP
+#undef HAVE_SEM_TIMEDWAIT
 
 #else
 /* We may need some replacement for stdarg.h here */

src/thread/pthread/SDL_syssem.c

@@ -103,8 +103,12 @@ int
 SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout)
 {
     int retval;
+#ifdef HAVE_SEM_TIMEDWAIT
     struct timeval now;
     struct timespec ts_timeout;
+#else
+    Uint32 end;
+#endif
 
     if (!sem) {
         SDL_SetError("Passed a NULL semaphore");
@@ -119,6 +123,7 @@ SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout)
         return SDL_SemWait(sem);
     }
 
+#ifdef HAVE_SEM_TIMEDWAIT
     /* Setup the timeout. sem_timedwait doesn't wait for
     * a lapse of time, but until we reach a certain time.
     * This time is now plus the timeout.
@@ -147,6 +152,15 @@ SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout)
     if (retval < 0) {
         SDL_SetError("sem_timedwait() failed");
     }
+#else
+    end = SDL_GetTicks() + timeout;
+    while ((retval = SDL_SemTryWait(sem)) == SDL_MUTEX_TIMEDOUT) {
+        if ((SDL_GetTicks() - end) >= 0) {
+            break;
+        }
+        SDL_Delay(0);
+    }
+#endif /* HAVE_SEM_TIMEDWAIT */
 
     return retval;
 }