Fix redundant clang-cl and msvc platform constraint for Bazel 8 compatibility and enable Bazel 8 presubmits in BCR.

PiperOrigin-RevId: 727052001

Author: zhangskz

.bcr/presubmit.yml

@@ -2,7 +2,7 @@ bcr_test_module:
   module_path: examples
   matrix:
     platform: ["debian10", "macos", "ubuntu2004", "windows"]
-    bazel: [7.x]
+    bazel: [7.x, 8.x]
 
   tasks:
     verify_targets:

WORKSPACE

@@ -97,10 +97,12 @@ load("@build_bazel_apple_support//lib:repositories.bzl", "apple_support_dependen
 
 apple_support_dependencies()
 
-load("@rules_cc//cc:repositories.bzl", "rules_cc_dependencies")
+load("@rules_cc//cc:repositories.bzl", "rules_cc_dependencies", "rules_cc_toolchains")
 
 rules_cc_dependencies()
 
+rules_cc_toolchains()
+
 # For `kt_jvm_library`
 load("@rules_kotlin//kotlin:repositories.bzl", "kotlin_repositories")
 

build_defs/BUILD.bazel

@@ -28,7 +28,6 @@ platform(
     constraint_values = [
         "@platforms//cpu:x86_64",
         "@platforms//os:windows",
-        "@bazel_tools//tools/cpp:clang-cl",
         # This is necessary for Bazel 7 compatibility with a MODULE.bazel file that still works in
         # Bazel 8.  Using cc_configure_extension from rules_cc produces a @local_config_cc
         # repository that's not compatible with @bazel_tools//tools/cpp:clang-cl from before
@@ -42,7 +41,6 @@ platform(
     constraint_values = [
         "@platforms//cpu:x86_64",
         "@platforms//os:windows",
-        "@bazel_tools//tools/cpp:msvc",
         # This may be necessary in case cc_configure_extension from rules_cc produces a
         # @local_config_cc repository that's not compatible with @bazel_tools//tools/cpp:msvc from
         # before Bazel 8, as with clang-cl above, to avoid silently falling back to clang-cl.