Added missing guards in implementation for PSP.

Thanks to Martin Gerhardy for pointing this out.

src/thread/psp/SDL_syscond.c

@@ -20,6 +20,8 @@
 */
 #include "../../SDL_internal.h"
 
+#if SDL_THREAD_PSP
+
 /* An implementation of condition variables using semaphores and mutexes */
 /*
    This implementation borrows heavily from the BeOS condition variable
@@ -217,4 +219,6 @@ SDL_CondWait(SDL_cond * cond, SDL_mutex * mutex)
     return SDL_CondWaitTimeout(cond, mutex, SDL_MUTEX_MAXWAIT);
 }
 
+#endif /* SDL_THREAD_PSP */
+
 /* vi: set ts=4 sw=4 expandtab: */

src/thread/psp/SDL_sysmutex.c

@@ -20,6 +20,8 @@
 */
 #include "../../SDL_internal.h"
 
+#if SDL_THREAD_PSP
+
 /* An implementation of mutexes using semaphores */
 
 #include "SDL_thread.h"
@@ -129,4 +131,6 @@ SDL_mutexV(SDL_mutex * mutex)
 #endif /* SDL_THREADS_DISABLED */
 }
 
+#endif /* SDL_THREAD_PSP */
+
 /* vi: set ts=4 sw=4 expandtab: */

src/thread/psp/SDL_syssem.c

@@ -20,6 +20,8 @@
 */
 #include "../../SDL_internal.h"
 
+#if SDL_THREAD_PSP
+
 /* Semaphore functions for the PSP. */
 
 #include <stdio.h>
@@ -153,5 +155,7 @@ int SDL_SemPost(SDL_sem *sem)
     return 0;
 }
 
+#endif /* SDL_THREAD_PSP */
+
 /* vim: ts=4 sw=4
  */

src/thread/psp/SDL_systhread.c

@@ -20,6 +20,8 @@
 */
 #include "../../SDL_internal.h"
 
+#if SDL_THREAD_PSP
+
 /* PSP thread management routines for SDL */
 
 #include <stdio.h>
@@ -104,5 +106,7 @@ int SDL_SYS_SetThreadPriority(SDL_ThreadPriority priority)
 
 }
 
+#endif /* SDL_THREAD_PSP */
+
 /* vim: ts=4 sw=4
  */