diff --git a/pkgs/development/libraries/protobuf/generic-v3.nix b/pkgs/development/libraries/protobuf/generic-v3.nix
index 39cf0a1741d..44ecdcb2f65 100644
--- a/pkgs/development/libraries/protobuf/generic-v3.nix
+++ b/pkgs/development/libraries/protobuf/generic-v3.nix
@@ -36,7 +36,7 @@ stdenv.mkDerivation rec {
 
   NIX_CFLAGS_COMPILE = with stdenv.lib;
     # gcc before 6 doesn't know this option
-    optionalString (hasPrefix "gcc-6" stdenv.cc.cc) "-Wno-error=misleading-indentation";
+    optionalString (hasPrefix "gcc-6" stdenv.cc.cc.name) "-Wno-error=misleading-indentation";
 
   meta = {
     description = "Google's data interchange format";
diff --git a/pkgs/os-specific/linux/kernel/perf.nix b/pkgs/os-specific/linux/kernel/perf.nix
index 0bfd8dfe700..fa4ac3b513d 100644
--- a/pkgs/os-specific/linux/kernel/perf.nix
+++ b/pkgs/os-specific/linux/kernel/perf.nix
@@ -34,7 +34,7 @@ stdenv.mkDerivation {
     "-Wno-error=cpp" "-Wno-error=bool-compare" "-Wno-error=deprecated-declarations"
   ]
     # gcc before 6 doesn't know these options
-    ++ stdenv.lib.optionals (hasPrefix "gcc-6" stdenv.cc.cc) [
+    ++ stdenv.lib.optionals (hasPrefix "gcc-6" stdenv.cc.cc.name) [
       "-Wno-error=unused-const-variable" "-Wno-error=misleading-indentation"
     ];