diff --git a/pkgs/development/compilers/gcc/7/default.nix b/pkgs/development/compilers/gcc/7/default.nix
index fab9b8fe7458..d671743ee629 100644
--- a/pkgs/development/compilers/gcc/7/default.nix
+++ b/pkgs/development/compilers/gcc/7/default.nix
@@ -254,6 +254,9 @@ stdenv.mkDerivation ({
     ++ (optional hostPlatform.isDarwin targetPackages.stdenv.cc.bintools)
     ;
 
+  # TODO: Use optionalString with next rebuild.
+  ${if (stdenv.cc.isClang && langFortran) then "NIX_CFLAGS_COMPILE" else null} = "-Wno-unused-command-line-argument";
+
   NIX_LDFLAGS = stdenv.lib.optionalString  hostPlatform.isSunOS "-lm -ldl";
 
   preConfigure = stdenv.lib.optionalString (hostPlatform.isSunOS && hostPlatform.is64bit) ''