1 files changed, 4 insertions, 0 deletions
diff --git a/nixpkgs/pkgs/applications/version-management/cvs/default.nix b/nixpkgs/pkgs/applications/version-management/cvs/default.nix
index 9f039c4ab004..4ee553c6c4be 100644
--- a/nixpkgs/pkgs/applications/version-management/cvs/default.nix
+++ b/nixpkgs/pkgs/applications/version-management/cvs/default.nix
@@ -40,6 +40,10 @@ stdenv.mkDerivation rec {
     "AR=${stdenv.cc.targetPrefix}ar"
   ];
 
+  env = lib.optionalAttrs stdenv.cc.isClang {
+    NIX_CFLAGS_COMPILE = "-Wno-implicit-function-declaration";
+  };
+
   doCheck = false; # fails 1 of 1 tests
 
   meta = with lib; {