diff -ur php7-pdo-7.4.8.orig/config.m4 php7-pdo-7.4.8/config.m4
--- php7-pdo-7.4.8.orig/config.m4	2020-07-09 08:57:18.000000000 +0000
+++ php7-pdo-7.4.8/config.m4	2020-07-23 10:56:38.431535388 +0000
@@ -12,6 +12,7 @@
   PHP_NEW_EXTENSION(pdo, pdo.c pdo_dbh.c pdo_stmt.c pdo_sql_parser.c pdo_sqlstate.c, $ext_shared)
   PHP_ADD_EXTENSION_DEP(pdo, spl, true)
   PHP_INSTALL_HEADERS(ext/pdo, [php_pdo.h php_pdo_driver.h php_pdo_error.h])
+  PHP_PROG_RE2C
 
   dnl so we always include the known-good working hack.
   PHP_ADD_MAKEFILE_FRAGMENT
Only in php7-pdo-7.4.8: config.m4~