Fix build under old linux systems

source/utils/CarlaPipeUtils.cpp

@@ -41,6 +41,9 @@
 # include <cerrno>
 # include <signal.h>
 # include <sys/wait.h>
+# ifndef F_SETPIPE_SZ
+#  define F_SETPIPE_SZ 1031
+# endif
 #endif
 
 #ifdef CARLA_OS_WIN