mark cc as optional

Author: wsmoses

deps/build_local.jl

@@ -132,8 +132,12 @@ build_cmd_list = [bazel_cmd, "build"]
 append!(build_cmd_list, ["-c", "$(build_kind)"])
 push!(build_cmd_list, "--action_env=JULIA=$(Base.julia_cmd().exec[1])")
 push!(build_cmd_list, "--repo_env=HERMETIC_PYTHON_VERSION=$(hermetic_python_version)")
-push!(build_cmd_list, "--repo_env=GCC_HOST_COMPILER_PATH=$(gcc_host_compiler_path)")
-push!(build_cmd_list, "--repo_env=CC=$(cc)")
+if !isempty(gcc_host_compiler_path)
+    push!(build_cmd_list, "--repo_env=GCC_HOST_COMPILER_PATH=$(gcc_host_compiler_path)")
+end
+if !isempty(cc)
+    push!(build_cmd_list, "--repo_env=CC=$(cc)")
+end
 push!(build_cmd_list, "--check_visibility=false")
 push!(build_cmd_list, "--verbose_failures")
 push!(build_cmd_list, "--jobs=$(parsed_args["jobs"])")