Use bind to redirect C++ crosstool configuration

This is a temporary workaround to enable the use
of a cc_configure() rules to auto-configure C++ toolchain.

--
MOS_MIGRATED_REVID=116140726

scripts/bootstrap/compile.sh

diff --git a/scripts/bootstrap/compile.sh b/scripts/bootstrap/compile.sh
index e585719..b7a5f3f 100755
--- a/scripts/bootstrap/compile.sh
+++ b/scripts/bootstrap/compile.sh
@@ -169,8 +169,10 @@
   done
 
   # Overwrite tools.WORKSPACE, this is only for the bootstrap binary
-  echo "local_repository(name = 'bazel_tools', path = __workspace_dir__)" \
-       > ${OUTPUT_DIR}/classes/com/google/devtools/build/lib/bazel/rules/tools.WORKSPACE
+  cat <<EOF >${OUTPUT_DIR}/classes/com/google/devtools/build/lib/bazel/rules/tools.WORKSPACE
+local_repository(name = 'bazel_tools', path = __workspace_dir__)
+bind(name = "cc_toolchain", actual = "@bazel_tools//tools/cpp:default-toolchain")
+EOF
 
   create_deploy_jar "libblaze" "com.google.devtools.build.lib.bazel.BazelMain" \
       ${OUTPUT_DIR}

src/main/java/com/google/devtools/build/lib/bazel/rules/tools.WORKSPACE

diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/tools.WORKSPACE b/src/main/java/com/google/devtools/build/lib/bazel/rules/tools.WORKSPACE
index 4059c9e..b080717 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/tools.WORKSPACE
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/tools.WORKSPACE
@@ -1 +1,2 @@
 local_repository(name = "bazel_tools", path = __embedded_dir__ + "/embedded_tools")
+bind(name = "cc_toolchain", actual = "@bazel_tools//tools/cpp:default-toolchain")

tools/cpp/BUILD

diff --git a/tools/cpp/BUILD b/tools/cpp/BUILD
index fd0a445..6e243e8 100644
--- a/tools/cpp/BUILD
+++ b/tools/cpp/BUILD
@@ -25,6 +25,12 @@
 # protobuf.
 filegroup(
     name = "toolchain",
+    srcs = ["//external:cc_toolchain"],
+)
+
+# Hardcoded toolchain, legacy behaviour.
+filegroup(
+    name = "default-toolchain",
     srcs = [
         ":cc-compiler-armeabi-v7a",
         ":cc-compiler-darwin",