diff -up grpc-1.82.0/config.m4.rpm grpc-1.82.0/config.m4
--- grpc-1.82.0/config.m4.rpm	2026-07-02 09:50:45.000000000 +0200
+++ grpc-1.82.0/config.m4	2026-07-03 08:09:35.143030893 +0200
@@ -19,9 +19,8 @@ if test "$PHP_GRPC" != "no"; then
 
   LIBS="-lpthread $LIBS"
 
-  dnl -Wno-error=attributes needed by UPB https://github.com/grpc/grpc/issues/42192
-  CFLAGS="-std=c11 -g -O2 -Wno-error=attributes"
-  CXXFLAGS="-std=c++17 -fno-exceptions -fno-rtti -g -O2 -Wno-error=attributes"
+  CFLAGS="$CFLAGS -std=c11  -Wno-error=attributes"
+  CXXFLAGS="$CXXFLAGS -std=c++17 -fno-exceptions -fno-rtti -Wno-error=attributes"
   GRPC_SHARED_LIBADD="-lpthread $GRPC_SHARED_LIBADD"
   PHP_REQUIRE_CXX()
   PHP_ADD_LIBRARY(pthread)