diff --git a/src/nix-build/nix-build.cc b/src/nix-build/nix-build.cc
index 99f77345..4f71fca1 100755
--- a/src/nix-build/nix-build.cc
+++ b/src/nix-build/nix-build.cc
@@ -372,6 +372,7 @@ void mainWrapped(int argc, char * * argv)
             env = newEnv;
             // NixOS hack: prevent /etc/bashrc from sourcing /etc/profile.
             env["__ETC_PROFILE_SOURCED"] = "1";
+            env["SKIP_CC_CVMFS"] = "1";
         }
 
         env["NIX_BUILD_TOP"] = env["TMPDIR"] = env["TEMPDIR"] = env["TMP"] = env["TEMP"] = tmp;