Fix mb_ord() crash if internal encoding not supported

enc_name can be NULL here. Take the name from the mbfl_encoding
instead.

Author: nikic

ext/mbstring/mbstring.c

@@ -4850,7 +4850,7 @@ static inline zend_long php_mb_ord(const char* str, size_t str_len, const char*
 
 	no_enc = enc->no_encoding;
 	if (php_mb_is_unsupported_no_encoding(no_enc)) {
-		php_error_docref(NULL, E_WARNING, "Unsupported encoding \"%s\"", enc_name);
+		php_error_docref(NULL, E_WARNING, "Unsupported encoding \"%s\"", enc->name);
 		return -1;
 	}
 

ext/mbstring/tests/mb_ord.phpt

@@ -19,6 +19,9 @@ var_dump(
 	mb_ord("\u{d800}", "utf-7"),
 	mb_ord("")
 );
+
+mb_internal_encoding("utf-7");
+mb_ord("");
 ?>
 --EXPECTF--
 bool(true)
@@ -29,11 +32,11 @@ Warning: mb_ord(): Unknown encoding "typo" %s 10
 
 Warning: mb_ord(): Unsupported encoding "pass" %s 11
 
-Warning: mb_ord(): Unsupported encoding "jis" %s 12
+Warning: mb_ord(): Unsupported encoding "JIS" in %s on line %d
 
-Warning: mb_ord(): Unsupported encoding "cp50222" %s 13
+Warning: mb_ord(): Unsupported encoding "CP50222" in %s on line %d
 
-Warning: mb_ord(): Unsupported encoding "utf-7" %s 14
+Warning: mb_ord(): Unsupported encoding "UTF-7" in %s on line %d
 
 Warning: mb_ord(): Empty string in %s on line %d
 bool(false)
@@ -42,3 +45,5 @@ bool(false)
 bool(false)
 bool(false)
 bool(false)
+
+Warning: mb_ord(): Unsupported encoding "UTF-7" in %s on line %d