bazel: make toolchain available at build time [WIP]

pkgs/development/tools/build-managers/bazel/default.nix

@@ -3,6 +3,8 @@
 , bazel
 , lr, xe, zip, unzip, bash, writeCBin, coreutils
 , which, python, gawk, gnused, gnutar, gnugrep, gzip, findutils
+, binutils
+, gcc
 # Apple dependencies
 , cctools, libcxx, CoreFoundation, CoreServices, Foundation
 # Allow to independently override the jdks used to build and run respectively
@@ -88,7 +90,7 @@ let
     #        ],
     #     )
     #
-    [ bash coreutils findutils gawk gnugrep gnutar gnused gzip which unzip ];
+    [ bash coreutils findutils gawk gnugrep gnutar gnused gzip which unzip binutils.bintools gcc ];
 
   # Java toolchain used for the build and tests
   javaToolchain = "@bazel_tools//tools/jdk:toolchain_host${buildJdkName}";
@@ -334,6 +336,13 @@ stdenv.mkDerivation rec {
 
   buildInputs = [
     buildJdk
+
+    # bazel detects default tool locations during build time using `which` (in
+    # tools/cpp/unic_cc_configure.bzl:_find_tool). Make sure the tools are in
+    # PATH.
+    # binutils.bintools # for ar, dwp, nm, objcopy, objdump, strip
+    # gcc # for ld, cpp, gcc
+    # gcc.cc # for gcov
   ];
 
   # when a command can’t be found in a bazel build, you might also
@@ -345,6 +354,11 @@ stdenv.mkDerivation rec {
     makeWrapper
     which
     customBash
+
+    # TODO add this in the correct way for cross compilation (e.g. buildInputs but so that it ends up in path)
+    binutils.bintools # for ar, dwp, nm, objcopy, objdump, strip
+    gcc # for ld, cpp, gcc
+    gcc.cc # for gcov
   ] ++ lib.optionals (stdenv.isDarwin) [ cctools libcxx CoreFoundation CoreServices Foundation ];
 
   # Bazel makes extensive use of symlinks in the WORKSPACE.