Fix undefined pthread_sigmask warning on FreeBSD (Juergen Lock)

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5537 c046a42c-6fe2-441c-8c8c-71466251a162

audio/sdlaudio.c

@@ -29,7 +29,7 @@
 #ifndef _WIN32
 #ifdef __sun__
 #define _POSIX_PTHREAD_SEMANTICS 1
-#elif defined(__OpenBSD__)
+#elif defined(__OpenBSD__) || defined(__FreeBSD__)
 #include <pthread.h>
 #endif
 #include <signal.h>