Fix [-Wimplicit-fallthrough] warnings in Main folder

Author: Girgias

main/main.c

@@ -1322,7 +1322,7 @@ static ZEND_COLD void php_error_cb(int orig_type, const char *error_filename, co
 				/* bad error in module startup - no way we can live with this */
 				exit(-2);
 			}
-		/* no break - intentionally */
+		fallthrough;
 		case E_ERROR:
 		case E_RECOVERABLE_ERROR:
 		case E_PARSE:

main/output.c

@@ -485,6 +485,7 @@ PHPAPI php_output_handler *php_output_handler_create_user(zval *output_handler,
 				handler = alias(Z_STRVAL_P(output_handler), Z_STRLEN_P(output_handler), chunk_size, flags);
 				break;
 			}
+			fallthrough;
 		default:
 			user = ecalloc(1, sizeof(php_output_handler_user_func_t));
 			if (SUCCESS == zend_fcall_info_init(output_handler, 0, &user->fci, &user->fcc, &handler_name, &error)) {
@@ -1014,7 +1015,7 @@ static inline php_output_handler_status_t php_output_handler_op(php_output_handl
 		case PHP_OUTPUT_HANDLER_NO_DATA:
 			/* handler ate all */
 			php_output_context_reset(context);
-			/* no break */
+			fallthrough;
 		case PHP_OUTPUT_HANDLER_SUCCESS:
 			/* no more buffered data */
 			handler->buffer.used = 0;

main/snprintf.c

@@ -749,6 +749,7 @@ static int format_converter(register buffy * odp, const char *fmt, va_list ap) /
 						fmt++;
 					}
 					/* these are promoted to int, so no break */
+					fallthrough;
 				default:
 					modifier = LM_STD;
 					break;
@@ -1143,6 +1144,7 @@ static int format_converter(register buffy * odp, const char *fmt, va_list ap) /
 					 * Note that we can't point s inside fmt because the
 					 * unknown <char> could be preceded by width etc.
 					 */
+				fallthrough;
 				default:
 					char_buf[0] = '%';
 					char_buf[1] = *fmt;

main/spprintf.c

@@ -356,6 +356,7 @@ static void xbuf_format_converter(void *xbuf, zend_bool is_char, const char *fmt
 						fmt++;
 					}
 					/* these are promoted to int, so no break */
+					fallthrough;
 				default:
 					modifier = LM_STD;
 					break;
@@ -749,6 +750,7 @@ static void xbuf_format_converter(void *xbuf, zend_bool is_char, const char *fmt
 					 * Note that we can't point s inside fmt because the
 					 * unknown <char> could be preceded by width etc.
 					 */
+				fallthrough;
 				default:
 					char_buf[0] = '%';
 					char_buf[1] = *fmt;