Add arg.h from sbase project.

git://git.suckless.org/sbase

arg.h

@@ -0,0 +1,55 @@
+/*
+ * Copy me if you can.
+ * by 20h
+ */
+
+#ifndef __ARG_H__
+#define __ARG_H__
+
+extern char *argv0;
+
+#define USED(x)		((void)(x))
+
+/* use main(int argc, char *argv[]) */
+#define ARGBEGIN	for (argv0 = *argv, argv++, argc--;\
+					argv[0] && argv[0][1]\
+					&& argv[0][0] == '-';\
+					argc--, argv++) {\
+				char _argc;\
+				char **_argv;\
+				int brk;\
+				if (argv[0][1] == '-' && argv[0][2] == '\0') {\
+					argv++;\
+					argc--;\
+					break;\
+				}\
+				for (brk = 0, argv[0]++, _argv = argv;\
+						argv[0][0] && !brk;\
+						argv[0]++) {\
+					if (_argv != argv)\
+						break;\
+					_argc = argv[0][0];\
+					switch (_argc)
+
+#define ARGEND			}\
+				USED(_argc);\
+			}\
+			USED(argv);\
+			USED(argc);
+
+#define ARGC()		_argc
+
+#define EARGF(x)	((argv[0][1] == '\0' && argv[1] == NULL)?\
+				((x), abort(), (char *)0) :\
+				(brk = 1, (argv[0][1] != '\0')?\
+					(&argv[0][1]) :\
+					(argc--, argv++, argv[0])))
+
+#define ARGF()		((argv[0][1] == '\0' && argv[1] == NULL)?\
+				(char *)0 :\
+				(brk = 1, (argv[0][1] != '\0')?\
+					(&argv[0][1]) :\
+					(argc--, argv++, argv[0])))
+
+#endif
+

slow.c

@@ -3,14 +3,19 @@
 #include <stdio.h>
 #include <unistd.h>
 
+#include "arg.h"
+
+char *argv0;
+
 int main(int argc, char *argv[]) {
 	char		buffer;
 	size_t		nread;
 	useconds_t	useconds	= 1000000; // default 1 second
 
-	if (argc == 2) {
-		useconds = atoi(argv[1]);
-	}
+	ARGBEGIN {
+	case 't':
+		useconds = atoi(ARGF());
+	} ARGEND;
 
 	while((nread = fread(&buffer, 1, sizeof buffer, stdin)) > 0) {
 		usleep(useconds);