8287122: Use gcc12 -ftrivial-auto-var-init=pattern in debug builds

Reviewed-by: erikj

Author: magicus

make/autoconf/flags-cflags.m4

@@ -481,6 +481,11 @@ AC_DEFUN([FLAGS_SETUP_CFLAGS_HELPER],
   else
     DEBUG_CFLAGS_JDK="-DDEBUG"
 
+    if test "x$TOOLCHAIN_TYPE" = xgcc; then
+      DEBUG_CFLAGS_JDK="DEBUG_CFLAGS_JDK -ftrivial-auto-var-init=pattern"
+      DEBUG_CFLAGS_JVM="-ftrivial-auto-var-init=pattern"
+    fi
+
     if test "x$TOOLCHAIN_TYPE" = xclang && test "x$OPENJDK_TARGET_OS" = xaix; then
       DEBUG_CFLAGS_JVM="-fpic -mcmodel=large"
     fi