diff --git a/pkgs/development/interpreters/python/cpython/2.7/default.nix b/pkgs/development/interpreters/python/cpython/2.7/default.nix
index d6ba795d20a..5ee88ebb881 100644
--- a/pkgs/development/interpreters/python/cpython/2.7/default.nix
+++ b/pkgs/development/interpreters/python/cpython/2.7/default.nix
@@ -258,7 +258,7 @@ in with passthru; stdenv.mkDerivation ({
     LDFLAGS = lib.optionalString (!stdenv.isDarwin) "-lgcc_s";
     inherit (mkPaths buildInputs) C_INCLUDE_PATH LIBRARY_PATH;
 
-    NIX_CFLAGS_COMPILE = optionalString stdenv.isDarwin "-msse2"
+    NIX_CFLAGS_COMPILE = optionalString (stdenv.targetPlatform.system == "x86_64-darwin") "-msse2"
       + optionalString stdenv.hostPlatform.isMusl " -DTHREAD_STACK_SIZE=0x100000";
     DETERMINISTIC_BUILD = 1;