lib, net: make isodigit() public and use it

There are at least two users of isodigit().  Let's make it a public
function of ctype.h.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/ctype.h

@@ -61,4 +61,10 @@ static inline char _tolower(const char c)
 	return c | 0x20;
 }
 
+/* Fast check for octal digit */
+static inline int isodigit(const char c)
+{
+	return c >= '0' && c <= '7';
+}
+
 #endif

lib/dynamic_debug.c

@@ -281,7 +281,6 @@ static inline int parse_lineno(const char *str, unsigned int *val)
  * allow the user to express a query which matches a format
  * containing embedded spaces.
  */
-#define isodigit(c)		((c) >= '0' && (c) <= '7')
 static char *unescape(char *str)
 {
 	char *in = str;

net/sunrpc/cache.c

@@ -1208,7 +1208,6 @@ EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
  * key and content are both parsed by cache
  */
 
-#define isodigit(c) (isdigit(c) && c <= '7')
 int qword_get(char **bpp, char *dest, int bufsize)
 {
 	/* return bytes copied, or -1 on error */