Fix missing resource.h inclusion

Closes JSC #43

maestro/core.c

@@ -49,6 +49,7 @@
 #include <inttypes.h>
 #include <string.h>
 #include <assert.h>
+#include <sys/resource.h>
 
 #include "maestro/i_state.h"
 #include "transport/transport.h"