Add ATTRIBUTE_FORMAT_FPTR macro for setting format specifier also on function pointers

This was available from gcc 3.1, so diable it before that
Update m_ctype.h to use the new macro

include/m_ctype.h

@@ -175,7 +175,7 @@ typedef struct my_charset_handler_st
   
   /* Charset dependant snprintf() */
   int  (*snprintf)(struct charset_info_st *, char *to, uint n, const char *fmt,
-		   ...) ATTRIBUTE_FORMAT(printf, 4, 5);
+		   ...) ATTRIBUTE_FORMAT_FPTR(printf, 4, 5);
   int  (*long10_to_str)(struct charset_info_st *, char *to, uint n, int radix,
 			long int val);
   int (*longlong10_to_str)(struct charset_info_st *, char *to, uint n,

include/my_global.h

@@ -431,9 +431,6 @@ typedef unsigned short ushort;
 #ifndef __attribute__
 # if !defined(__GNUC__)
 #  define __attribute__(A)
-# elif defined (__QNXNTO__)
-   /* qcc defines GNUC */
-#  define __attribute__(A)
 # elif GCC_VERSION < 2008
 #  define __attribute__(A)
 # elif defined(__cplusplus) && GCC_VERSION < 3004
@@ -450,6 +447,19 @@ typedef unsigned short ushort;
 # define ATTRIBUTE_FORMAT(style, m, n) __attribute__((format(style, m, n)))
 #endif
 
+/*
+   __attribute__((format(...))) on a function pointer is not supported
+   until  gcc 3.1
+*/
+#ifndef ATTRIBUTE_FORMAT_FPTR
+# if (GCC_VERSION >= 3001)
+#  define ATTRIBUTE_FORMAT_FPTR(style, m, n) ATTRIBUTE_FORMAT(style, m, n)
+# else
+#  define ATTRIBUTE_FORMAT_FPTR(style, m, n)
+# endif /* GNUC >= 3.1 */
+#endif
+
+
 /* From old s-system.h */
 
 /*