Add support for obsolete -NUM arguments in arg.h

Fix naming, _brk, _argc and _argv are reserved for the
implementation.

Thanks to nsz@port70.net for reporting this, the mail excerpt below.

"actually __.* and _[A-Z].* are reserved for any usage and _.* is
reserved for file scope identifiers"

We just rename them to brk_, argc_ and argv_.

arg.h

@@ -13,38 +13,51 @@ extern char *argv0;
 					argv[0] && argv[0][1]\
 					&& argv[0][0] == '-';\
 					argc--, argv++) {\
-				char _argc;\
+				char argc_;\
-				char **_argv;\
+				char **argv_;\
-				int _brk;\
+				int brk_;\
 				if (argv[0][1] == '-' && argv[0][2] == '\0') {\
 					argv++;\
 					argc--;\
 					break;\
 				}\
-				for (_brk = 0, argv[0]++, _argv = argv;\
+				for (brk_ = 0, argv[0]++, argv_ = argv;\
-						argv[0][0] && !_brk;\
+						argv[0][0] && !brk_;\
 						argv[0]++) {\
-					if (_argv != argv)\
+					if (argv_ != argv)\
 						break;\
-					_argc = argv[0][0];\
+					argc_ = argv[0][0];\
-					switch (_argc)
+					switch (argc_)
+
+/* Handles obsolete -NUM syntax */
+#define ARGNUM				case '0':\
+					case '1':\
+					case '2':\
+					case '3':\
+					case '4':\
+					case '5':\
+					case '6':\
+					case '7':\
+					case '8':\
+					case '9'
 
 #define ARGEND			}\
 			}
 
-#define ARGC()		_argc
+#define ARGC()		argc_
+
+#define ARGNUMF(base)	(brk_ = 1, estrtol(argv[0], (base)))
 
 #define EARGF(x)	((argv[0][1] == '\0' && argv[1] == NULL)?\
 				((x), abort(), (char *)0) :\
-				(_brk = 1, (argv[0][1] != '\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')?\
+				(brk_ = 1, (argv[0][1] != '\0')?\
 					(&argv[0][1]) :\
 					(argc--, argv++, argv[0])))
 
 #endif
-