diff --git a/pkgs/tools/archivers/p7zip/default.nix b/pkgs/tools/archivers/p7zip/default.nix
index 4886217211d..5430c2cb73e 100644
--- a/pkgs/tools/archivers/p7zip/default.nix
+++ b/pkgs/tools/archivers/p7zip/default.nix
@@ -20,6 +20,10 @@ stdenv.mkDerivation rec {
 
     # I think this is a typo and should be CXX? Either way let's kill it
     sed -i '/XX=\/usr/d' makefile.macosx_llvm_64bits
+  '' + stdenv.lib.optionalString (stdenv.buildPlatform != stdenv.hostPlatform) ''
+    substituteInPlace makefile.machine \
+      --replace 'CC=gcc'  'CC=${stdenv.cc.targetPrefix}gcc' \
+      --replace 'CXX=g++' 'CXX=${stdenv.cc.targetPrefix}g++'
   '';
 
   preConfigure = ''