From 2774cee4105b644eaa23478dfceeca936122d4e6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Milan=20P=C3=A4ssler?= <milan@petabyte.dev>
Date: Thu, 22 Apr 2021 12:57:24 +0200
Subject: [PATCH] llvm_12: add back `--gcc-toolchain` logic

In master commit 071030840252273acf05c9902458d4db5bdd71ab this was
removed from all LLVM versions, but we don't this commit on 20.09,
so when LLVM 12 was backported, there was no `--gcc-toolchain` in
`llvmPackages_12.stdenv`.
---
 pkgs/development/compilers/llvm/12/default.nix | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pkgs/development/compilers/llvm/12/default.nix b/pkgs/development/compilers/llvm/12/default.nix
index e34399381687..40febfec1be9 100644
--- a/pkgs/development/compilers/llvm/12/default.nix
+++ b/pkgs/development/compilers/llvm/12/default.nix
@@ -29,6 +29,8 @@ let
       ln -s "${targetLlvmLibraries.compiler-rt.out}/lib" "$rsrc/lib"
       ln -s "${targetLlvmLibraries.compiler-rt.out}/share" "$rsrc/share"
       echo "-resource-dir=$rsrc" >> $out/nix-support/cc-cflags
+    '' + lib.optionalString (stdenv.targetPlatform.isLinux && !(stdenv.targetPlatform.useLLVM or false)) ''
+      echo "--gcc-toolchain=${gccForLibs}" >> $out/nix-support/cc-cflags
     '';
   in {