[apr] error: use of undeclared identifier 'NSIG'

libs/apr/include/apr_general.h

@@ -29,6 +29,10 @@
 #include "apr_pools.h"
 #include "apr_errno.h"
 
+#if !defined(_ANSI_SOURCE) && defined(_DARWIN_C_SOURCE)
+#define NSIG __DARWIN_NSIG
+#endif
+
 #if APR_HAVE_SIGNAL_H
 #include <signal.h>
 #endif