diff --git a/configure.ac b/configure.ac
index 84aa48d7..aff89c1b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -396,6 +396,8 @@ if test -n "$WARN_CFLAGS"; then
     nw="$nw -Wswitch-default" # TODO: Enable someday. Too noisy for now
     nw="$nw -Wpedantic" # GCC 11. Too noisy, will never be supported
     nw="$nw -Wnested-externs" # Stylistic choice and we do use it in hsts code
+    nw="$nw -Wc90-c99-compat" # gcc-12, we use C99
+    nw="$nw -Wlong-long" # gcc-12, we use C99
     if test "$cross_compiling" = yes; then
       nw="$nw -Wformat"
     fi