Something

diff -rN -u old-stream-engine/src/stream-engine-main.c new-stream-engine/src/stream-engine-main.c
--- old-stream-engine/src/stream-engine-main.c  2006-08-11 16:06:32.000000000 +0200
+++ new-stream-engine/src/stream-engine-main.c  2006-08-11 16:06:32.000000000 +0200
@@ -21,7 +21,9 @@
 #include "config.h"
 
 #include <signal.h>
+#if (_POSIX_PRIORITY_SCHEDULING - 0) >=  200112L
 #define USE_REALTIME
+#endif
 #ifdef USE_REALTIME
 #include <stdlib.h>
 #include <string.h>
@@ -188,8 +190,10 @@
 }
 
 int main(int argc, char **argv) {
+#ifdef USE_REALTIME
   int rt_mode;
   char *rt_env;
+#endif // USE_REALTIME
 
   signal (SIGBUS, got_sigbus);
   signal (SIGSEGV, got_segv);