Add -Wno-strict-prototypes compiler flag to readline extension

Author: Girgias

ext/readline/config.m4

@@ -137,6 +137,7 @@ elif test "$PHP_LIBEDIT" != "no"; then
 fi
 
 if test "$PHP_READLINE" != "no" || test "$PHP_LIBEDIT" != "no"; then
-  PHP_NEW_EXTENSION(readline, readline.c readline_cli.c, $ext_shared, cli)
+  dnl Add -Wno-strict-prototypes as depends on user libs
+  PHP_NEW_EXTENSION(readline, readline.c readline_cli.c, $ext_shared, cli, "-Wno-strict-prototypes")
   PHP_SUBST(READLINE_SHARED_LIBADD)
 fi