move symbol definition for Cygwin (fix #506)

common.c

@@ -25,12 +25,6 @@
 #include <sys/prctl.h>
 #endif
 
-/* Added to make the code compilable under CYGWIN
- * */
-#ifndef SA_NOCLDWAIT
-#define SA_NOCLDWAIT 0
-#endif
-
 /* Make use of systemd socket activation
  * */
 #ifdef SYSTEMD

common.h

@@ -9,6 +9,13 @@
 #define FD_SETSIZE 4096
 #endif
 
+/* Cygwin does not define some symbols
+ * */
+#ifndef SA_NOCLDWAIT
+#define SA_NOCLDWAIT 0
+#endif
+
+
 #define _GNU_SOURCE
 #include <sys/types.h>
 #include <fcntl.h>