diff --git a/pkgs/tools/X11/xprompt/default.nix b/pkgs/tools/X11/xprompt/default.nix
index 69149b3889b8..e8633d1eb383 100644
--- a/pkgs/tools/X11/xprompt/default.nix
+++ b/pkgs/tools/X11/xprompt/default.nix
@@ -36,7 +36,7 @@ stdenv.mkDerivation rec {
     in
     optionalString (conf != null) "cp ${configFile} config.h";
 
-  makeFlags = [ "PREFIX=$(out)" ];
+  makeFlags = [ "CC:=$(CC)" "PREFIX=$(out)" ];
 
   passthru.updateScript = nix-update-script {
     attrPath = pname;