diff --git a/pkgs/development/libraries/cogl/default.nix b/pkgs/development/libraries/cogl/default.nix
index c07c8b7c1501..987d90e26995 100644
--- a/pkgs/development/libraries/cogl/default.nix
+++ b/pkgs/development/libraries/cogl/default.nix
@@ -85,11 +85,15 @@ stdenv.mkDerivation rec {
   buildInputs = lib.optionals pangoSupport [ pango cairo harfbuzz ]
     ++ lib.optionals stdenv.isDarwin [ OpenGL ];
 
-  COGL_PANGO_DEP_CFLAGS = toString (lib.optionals (stdenv.isDarwin && pangoSupport) [
-    "-I${pango.dev}/include/pango-1.0"
-    "-I${cairo.dev}/include/cairo"
-    "-I${harfbuzz.dev}/include/harfbuzz"
-  ]);
+  env = {
+    COGL_PANGO_DEP_CFLAGS = toString (lib.optionals (stdenv.isDarwin && pangoSupport) [
+      "-I${pango.dev}/include/pango-1.0"
+      "-I${cairo.dev}/include/cairo"
+      "-I${harfbuzz.dev}/include/harfbuzz"
+    ]);
+  } // lib.optionalAttrs stdenv.cc.isClang {
+    NIX_CFLAGS_COMPILE = "-Wno-error=implicit-function-declaration";
+  };
 
   #doCheck = true; # all tests fail (no idea why)