Register both windows compilers to enable cross compilation

Copybara Import from bazelbuild#432

BEGIN_PUBLIC
Register both windows compilers to enable cross compilation (bazelbuild#432)

There is a perfectly good cross compiler for the other Windows variant (arm64 vs x86).  The only problem is that it doesn't get registered by default, so it isn't easily available.  Register both of them and let toolchain selection pick the right one automatically.

Closes bazelbuild#432
END_PUBLIC

COPYBARA_INTEGRATE_REVIEW=bazelbuild#432 from AustinSchuh:windows_cross_compile a738de7
PiperOrigin-RevId: 854483022
Change-Id: Ie366916d725b7e140665686f52f22eeee18a7614

Author: AustinSchuh

cc/private/toolchain/BUILD.windows_toolchains.tpl

@@ -0,0 +1,34 @@
+load("@platforms//host:constraints.bzl", "HOST_CONSTRAINTS")
+
+toolchain(
+    name = "cc-toolchain-arm64_windows",
+    exec_compatible_with = HOST_CONSTRAINTS,
+    target_compatible_with = [
+        "@platforms//cpu:arm64",
+        "@platforms//os:windows",
+    ],
+    toolchain = "@local_config_cc//:cc-compiler-arm64_windows",
+    toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
+)
+
+toolchain(
+    name = "cc-toolchain-x64_windows",
+    exec_compatible_with = HOST_CONSTRAINTS,
+    target_compatible_with = [
+        "@platforms//cpu:x86_64",
+        "@platforms//os:windows",
+    ],
+    toolchain = "@local_config_cc//:cc-compiler-x64_windows",
+    toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
+)
+
+toolchain(
+    name = "cc-toolchain-armeabi-v7a",
+    exec_compatible_with = HOST_CONSTRAINTS,
+    target_compatible_with = [
+        "@platforms//cpu:armv7",
+        "@platforms//os:android",
+    ],
+    toolchain = "@local_config_cc//:cc-compiler-armeabi-v7a",
+    toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
+)

cc/private/toolchain/cc_configure.bzl

@@ -33,12 +33,17 @@ def cc_autoconf_toolchains_impl(repository_ctx):
     should_detect_cpp_toolchain = "BAZEL_DO_NOT_DETECT_CPP_TOOLCHAIN" not in env or env["BAZEL_DO_NOT_DETECT_CPP_TOOLCHAIN"] != "1"
 
     if should_detect_cpp_toolchain:
+        if repository_ctx.os.name.lower().find("windows") != -1:
+            build_path = "@rules_cc//cc/private/toolchain:BUILD.windows_toolchains.tpl"
+        else:
+            build_path = "@rules_cc//cc/private/toolchain:BUILD.toolchains.tpl"
         paths = resolve_labels(repository_ctx, [
-            "@rules_cc//cc/private/toolchain:BUILD.toolchains.tpl",
+            build_path,
         ])
+
         repository_ctx.template(
             "BUILD",
-            paths["@rules_cc//cc/private/toolchain:BUILD.toolchains.tpl"],
+            paths[build_path],
             {"%{name}": get_cpu_value(repository_ctx)},
         )
     else: