pkgs.withCFlags

Modify a stdenv so that it builds binaries with the specified list of compilerFlags appended and passed to the compiler.

This example would recompile every derivation on the system with -funroll-loops and -O3 passed to each gcc invocation.

Example: nixpkgs.overlays = [ (self: super: { stdenv = super.withCFlags [ "-funroll-loops" "-O3" ] super.stdenv; }) ];

Noogle detected

withCFlags =
    compilerFlags: stdenv:
    stdenv.override (old: {
      mkDerivationFromStdenv = extendMkDerivationArgs old (args: {
        env = (args.env or { }) // {
          NIX_CFLAGS_COMPILE = toString (args.env.NIX_CFLAGS_COMPILE or "") + " ${toString compilerFlags}";
        };
      });
    });