fix build: readline support must be disabled by default in phpdbg

Author: krakjoe

sapi/phpdbg/config.m4

@@ -12,7 +12,7 @@ PHP_ARG_ENABLE(phpdbg-debug, for phpdbg debug build,
 [  --enable-phpdbg-debug      Build phpdbg in debug mode], no, no)
 
 PHP_ARG_ENABLE(phpdbg-readline, for phpdbg readline support,
-[  --enable-phpdbg-readline   Enable readline support in phpdbg (depends on static ext/readline)], yes, yes)
+[  --enable-phpdbg-readline   Enable readline support in phpdbg (depends on static ext/readline)], no, no)
 
 if test "$BUILD_PHPDBG" = "" && test "$PHP_PHPDBG" != "no"; then
   AC_HEADER_TIOCGWINSZ