gnats: format hardened flag isn't supported

flokli · flokli · commit 07c40561791f · 2020-12-23T01:51:14.000+01:00
When invoking a simple Ada program with `gcc` from `gnats10`, the following warnings are shown: ``` $ gcc -c conftest.adb gnat1: warning: command-line option ‘-Wformat=1’ is valid for C/C++/ObjC/ObjC++ but not for Ada gnat1: warning: command-line option ‘-Wformat-security’ is valid for C/C++/ObjC/ObjC++ but not for Ada gnat1: warning: ‘-Werror=’ argument ‘-Werror=format-security’ is not valid for Ada $ echo $? 0 ``` This is only spammy when compiling Ada programs inside a Nix derivation, but certain configure scripts (such as the ./configure script from the gcc that's built by coreboot's `make crossgcc` command) fail entirely when getting that warning output. https://nixos.wiki/wiki/Coreboot currently suggests manually running > NIX_HARDENING_ENABLE="${NIX_HARDENING_ENABLE/ format/}" make crossgcc … but actually teaching the nixpkgs-provided cc wrapper that `format` isn't supported as a hardening flag seems to be the more canonical way to do this in nixpgks. After this, Ada programs still compile: ``` $ gcc -c conftest.adb $ echo $? 0 ``` And the compiler output is empty.
diff --git a/pkgs/build-support/cc-wrapper/default.nix b/pkgs/build-support/cc-wrapper/default.nix
@@ -437,7 +437,7 @@ stdenv.mkDerivation {
     '' + optionalString targetPlatform.isNetBSD ''
       hardening_unsupported_flags+=" stackprotector fortify"
     '' + optionalString cc.langAda or false ''
-      hardening_unsupported_flags+=" stackprotector strictoverflow"
+      hardening_unsupported_flags+=" format stackprotector strictoverflow"
     '' + optionalString cc.langD or false ''
       hardening_unsupported_flags+=" format"
     '' + optionalString targetPlatform.isWasm ''
