iverilog: set correct build compilers (#369623)

Author: FliegendeWurst

pkgs/by-name/iv/iverilog/package.nix

@@ -13,6 +13,7 @@
   python3,
   readline,
   zlib,
+  buildPackages,
 }:
 
 stdenv.mkDerivation rec {
@@ -33,8 +34,8 @@ stdenv.mkDerivation rec {
     gperf
   ];
 
-  CC_FOR_BUILD = "${stdenv.cc}/bin/cc";
-  CXX_FOR_BUILD = "${stdenv.cc}/bin/c++";
+  CC_FOR_BUILD = "${buildPackages.stdenv.cc}/bin/cc";
+  CXX_FOR_BUILD = "${buildPackages.stdenv.cc}/bin/c++";
 
   patches = [
     # NOTE(jleightcap): `-Werror=format-security` warning patched shortly after release, backport the upstream fix