Fix for cross compile

Added double brackets so brackets could be used within test program

auxdir/x_ac_printf_null.m4

@@ -37,7 +37,7 @@ AC_DEFUN([X_AC_PRINTF_NULL], [
   AC_RUN_IFELSE([AC_LANG_PROGRAM([
 	#include <stdio.h>
 	#include <stdlib.h>],
-	[ char tmp='\0'; char *n=NULL; snprintf(&tmp,1,"%s",n); exit(0); ])],
+	[[ char tmp[8]; char *n=NULL; snprintf(tmp,8,"%s",n); exit(0); ]])],
     printf_null_ok=yes,
     printf_null_ok=no,
     printf_null_ok=yes)

configure

@@ -22957,7 +22957,7 @@ else
 int
 main ()
 {
- char tmp='\0'; char *n=NULL; snprintf(&tmp,1,"%s",n); exit(0);
+ char tmp[8]; char *n=NULL; snprintf(tmp,8,"%s",n); exit(0);
   ;
   return 0;
 }