Make sure sem_wait didn't return early with EINTR. Fixes Bugzilla #231.

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%401816

src/thread/dc/SDL_syssem.c

@@ -19,6 +19,9 @@
     Sam Lantinga
     slouken@libsdl.org
 */
+
+#include <errno.h>
+
 #include "SDL_config.h"
 
 /* An implementation of semaphores using mutexes and condition variables */
@@ -135,13 +138,15 @@ int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout)
 
 int SDL_SemWait(SDL_sem *sem)
 {
+	int retval;
+
 	if ( ! sem ) {
 		SDL_SetError("Passed a NULL semaphore");
 		return -1;
 	}
 
-	sem_wait(&sem->sem);
-	return 0;
+	while ( ((retval = sem_wait(&sem->sem)) == -1) && (errno == EINTR) ) {}
+	return retval;
 }
 
 Uint32 SDL_SemValue(SDL_sem *sem)

src/thread/pthread/SDL_syssem.c

@@ -23,6 +23,7 @@
 
 #include <pthread.h>
 #include <semaphore.h>
+#include <errno.h>
 
 #include "SDL_thread.h"
 #include "SDL_timer.h"
@@ -86,7 +87,7 @@ int SDL_SemWait(SDL_sem *sem)
 		return -1;
 	}
 
-	retval = sem_wait(&sem->sem);
+	while ( ((retval = sem_wait(&sem->sem)) == -1) && (errno == EINTR) ) {}
 	if ( retval < 0 ) {
 		SDL_SetError("sem_wait() failed");
 	}

src/thread/riscos/SDL_syssem.c

@@ -19,6 +19,9 @@
     Sam Lantinga
     slouken@libsdl.org
 */
+
+#include <errno.h>
+
 #include "SDL_config.h"
 
 /* RISC OS semiphores based on linux code */
@@ -132,7 +135,7 @@ int SDL_SemWait(SDL_sem *sem)
 		return -1;
 	}
 
-	retval = sem_wait(sem->sem);
+	while ( ((retval = sem_wait(sem->sem)) == -1) && (errno == EINTR) ) {}
 	if ( retval < 0 ) {
 		SDL_SetError("sem_wait() failed");
 	}