strcmp(1): without <sysexits.h> fall back to ANSI C

src/strcmp.c

@@ -1,6 +1,7 @@
 #include <stdio.h> /* fprintf(3), stderr */
-#ifndef EX_USAGE
-#	include <sysexits.h> /* EX_USAGE */
+#include <stdlib.h> /* EXIT_FAILURE */
+#if !defined EX_USAGE
+#	define EX_USAGE EXIT_FAILURE
 #endif
 
 static char *program_name = "strcmp";