GNUmakefile, intcmp(1), npc(1), scrut(1), str(1), strcmp(1), include/sysexits.h: added fallback header file for when systems don’t have sysexits.h(3)

src/scrut.c

@@ -19,13 +19,11 @@
 #include <stdio.h> /* fprintf(3), stderr, NULL */
 #include <stdlib.h> /* EXIT_FAILURE */
 #include <string.h> /* strchr(3) */
-#ifndef EX_USAGE
-#	define EX_USAGE EXIT_FAILURE
-#endif
 #include <unistd.h> /* access(3), getopt(3), F_OK, R_OK, W_OK, X_OK */
 #include <sys/stat.h> /* lstat(3), stat struct, S_ISBLK, S_ISCHR, S_ISDIR,
                        * S_ISFIFO, S_ISGID, S_ISREG, S_ISLNK, S_ISSOCK,
                        * S_ISUID, S_ISVTX */
+#include <sysexits.h>
 
 static char args[] = "bcdefghkprsuwxLS";
 static char ops[(sizeof args) / (sizeof *args)];