From 77550df8e68b5034d6a434c709be69adee1940cc Mon Sep 17 00:00:00 2001
From: Matthew Bauer <mjbauer95@gmail.com>
Date: Sat, 26 Jan 2019 10:17:57 -0500
Subject: [PATCH] cc-wrapper: add libcxx for libcxxClang

clang needs to find headers + libraries for compiling with libc++. We
need to add a libcxx argument to cc-wrapper. This means you do not
have to pass in c++ headers directly.

This resolves the last case remaining of #30670. Darwin clang++ now
works properly.

Fixes #30670
---
 pkgs/build-support/cc-wrapper/default.nix     | 14 +++++++++-----
 pkgs/development/compilers/llvm/5/default.nix |  1 +
 pkgs/development/compilers/llvm/6/default.nix |  1 +
 pkgs/development/compilers/llvm/7/default.nix |  1 +
 4 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/pkgs/build-support/cc-wrapper/default.nix b/pkgs/build-support/cc-wrapper/default.nix
index 47c992d1f6ba..75a05d5277bf 100644
--- a/pkgs/build-support/cc-wrapper/default.nix
+++ b/pkgs/build-support/cc-wrapper/default.nix
@@ -13,6 +13,7 @@
 , extraPackages ? [], extraBuildCommands ? ""
 , isGNU ? false, isClang ? cc.isClang or false, gnugrep ? null
 , buildPackages ? {}
+, libcxx ? null
 }:
 
 with stdenvNoCC.lib;
@@ -44,8 +45,11 @@ let
   # The wrapper scripts use 'cat' and 'grep', so we may need coreutils.
   coreutils_bin = if nativeTools then "" else getBin coreutils;
 
-  default_cxx_stdlib_compile = optionalString (targetPlatform.isLinux && !(cc.isGNU or false) && !nativeTools && cc ? gcc)
-    "-isystem $(echo -n ${cc.gcc}/include/c++/*) -isystem $(echo -n ${cc.gcc}/include/c++/*)/$(${cc.gcc}/bin/gcc -dumpmachine)";
+  default_cxx_stdlib_compile = if (targetPlatform.isLinux && !(cc.isGNU or false) && !nativeTools && cc ? gcc) then
+    "-isystem $(echo -n ${cc.gcc}/include/c++/*) -isystem $(echo -n ${cc.gcc}/include/c++/*)/$(${cc.gcc}/bin/gcc -dumpmachine)"
+  else if targetPlatform.isDarwin && (libcxx != null) && (cc.isClang or false) then
+    "-isystem ${libcxx}/include/c++/v1"
+  else "";
 
   # The "infix salt" is a arbitrary string added in the middle of env vars
   # defined by cc-wrapper's hooks so that multiple cc-wrappers can be used
@@ -256,9 +260,9 @@ stdenv.mkDerivation {
 
       echo "$ccLDFlags" > $out/nix-support/cc-ldflags
       echo "$ccCFlags" > $out/nix-support/cc-cflags
-    ''
-
-    + optionalString propagateDoc ''
+    '' + optionalString (targetPlatform.isDarwin && (libcxx != null) && (cc.isClang or false)) ''
+      echo " -L${libcxx}/lib" >> $out/nix-support/cc-ldflags
+    '' + optionalString propagateDoc ''
       ##
       ## Man page and info support
       ##
diff --git a/pkgs/development/compilers/llvm/5/default.nix b/pkgs/development/compilers/llvm/5/default.nix
index 68ee80fa7a62..6807240df81e 100644
--- a/pkgs/development/compilers/llvm/5/default.nix
+++ b/pkgs/development/compilers/llvm/5/default.nix
@@ -59,6 +59,7 @@ let
 
     libcxxClang = wrapCCWith rec {
       cc = tools.clang-unwrapped;
+      libcxx = targetLlvmLibraries.libcxx;
       extraPackages = [
         targetLlvmLibraries.libcxx
         targetLlvmLibraries.libcxxabi
diff --git a/pkgs/development/compilers/llvm/6/default.nix b/pkgs/development/compilers/llvm/6/default.nix
index 5ee551f6b6b1..ae51c19ec728 100644
--- a/pkgs/development/compilers/llvm/6/default.nix
+++ b/pkgs/development/compilers/llvm/6/default.nix
@@ -59,6 +59,7 @@ let
 
     libcxxClang = wrapCCWith rec {
       cc = tools.clang-unwrapped;
+      libcxx = targetLlvmLibraries.libcxx;
       extraPackages = [
         targetLlvmLibraries.libcxx
         targetLlvmLibraries.libcxxabi
diff --git a/pkgs/development/compilers/llvm/7/default.nix b/pkgs/development/compilers/llvm/7/default.nix
index 47c6e9e383f3..3f1192d96263 100644
--- a/pkgs/development/compilers/llvm/7/default.nix
+++ b/pkgs/development/compilers/llvm/7/default.nix
@@ -59,6 +59,7 @@ let
 
     libcxxClang = wrapCCWith rec {
       cc = tools.clang-unwrapped;
+      libcxx = targetLlvmLibraries.libcxx;
       extraPackages = [
         targetLlvmLibraries.libcxx
         targetLlvmLibraries.libcxxabi