Revert link_hack change (#73)

This restores support for 8.x, and makes 9.x require a patch on rules_cc
(which users have to opt into)

The checking changed with 9.x in
bazelbuild/bazel@26760a0
which is strict for external repos

Author: keith

.github/workflows/ci.yaml

@@ -18,6 +18,7 @@ jobs:
           - ubuntu-latest
         bazel:
           - 8.x
+          - 9.x
           - latest
           - last_rc
           - last_green

MODULE.bazel

@@ -6,9 +6,19 @@ module(
 
 bazel_dep(name = "bazel_skylib", version = "1.7.1")
 bazel_dep(name = "platforms", version = "0.0.11")
-bazel_dep(name = "rules_cc", version = "0.1.1")
+bazel_dep(name = "rules_cc", version = "0.2.16")
 bazel_dep(name = "rules_python", version = "1.0.0")
 
+# Apply this patch in your project if you want to use shared libraries with mojo
+single_version_override(
+    module_name = "rules_cc",
+    patch_strip = 1,
+    patches = [
+        # https://github.com/bazelbuild/rules_cc/pull/578
+        "//tools:rules_cc.patch",
+    ],
+)
+
 mojo = use_extension("//mojo:extensions.bzl", "mojo")
 mojo.toolchain()
 mojo.gpu_toolchains()
@@ -56,3 +66,9 @@ versions(
     dev_dependency = True,
     python_versions = _PYTHON_VERSIONS,
 )
+
+link_hack = use_repo_rule("//mojo/private:link_hack.bzl", "link_hack")
+
+link_hack(
+    name = "build_bazel_rules_android",  # See link_hack.bzl for details
+)

tools/build_defs/android/link_hack.bzl mojo/private/link_hack.bzltools/build_defs/android/link_hack.bzl renamed to mojo/private/link_hack.bzl

@@ -3,7 +3,15 @@
 https://github.com/bazelbuild/bazel/pull/23838
 """
 
+def _link_hack_impl(rctx):
+    rctx.file("BUILD.bazel", "")
+    rctx.file("link_hack.bzl", """\
 load("@rules_cc//cc/common:cc_common.bzl", "cc_common")
 
 def link_hack(**kwargs):
     return cc_common.link(**kwargs)
+""")
+
+link_hack = repository_rule(
+    implementation = _link_hack_impl,
+)

mojo/private/mojo_binary_test.bzl

@@ -3,11 +3,11 @@
 load("@bazel_skylib//lib:paths.bzl", "paths")
 load("@bazel_skylib//rules:common_settings.bzl", "BuildSettingInfo")
 load("@bazel_tools//tools/cpp:toolchain_utils.bzl", "find_cpp_toolchain", "use_cpp_toolchain")
+load("@build_bazel_rules_android//:link_hack.bzl", "link_hack")  # See link_hack.bzl for details
 load("@rules_cc//cc/common:cc_common.bzl", "cc_common")
 load("@rules_cc//cc/common:cc_info.bzl", "CcInfo")
 load("@rules_python//python:py_info.bzl", "PyInfo")
 load("//mojo:providers.bzl", "MojoInfo")
-load("//tools/build_defs/android:link_hack.bzl", "link_hack")  # See link_hack.bzl for details
 load(":transitions.bzl", "python_version_transition")
 load(":utils.bzl", "MOJO_EXTENSIONS", "collect_mojoinfo")
 

tools/build_defs/android/BUILD.bazel tools/BUILD.bazeltools/build_defs/android/BUILD.bazel renamed to tools/BUILD.bazel

@@ -0,0 +1,30 @@
+diff --git a/cc/private/cc_common.bzl b/cc/private/cc_common.bzl
+index 69d6db11..82e9c49b 100644
+--- a/cc/private/cc_common.bzl
++++ b/cc/private/cc_common.bzl
+@@ -85,7 +85,7 @@ def _link(
+         additional_linkstamp_defines = _UNBOUND,
+         always_link = _UNBOUND,
+         link_artifact_name_suffix = _UNBOUND,
+-        main_output = _UNBOUND,
++        main_output = None,
+         use_shareable_artifact_factory = _UNBOUND,
+         build_config = _UNBOUND,
+         emit_interface_shared_library = _UNBOUND):
+@@ -103,7 +103,6 @@ def _link(
+        additional_linkstamp_defines != _UNBOUND or \
+        always_link != _UNBOUND or \
+        link_artifact_name_suffix != _UNBOUND or \
+-       main_output != _UNBOUND or \
+        use_shareable_artifact_factory != _UNBOUND or \
+        build_config != _UNBOUND or \
+        emit_interface_shared_library != _UNBOUND:
+@@ -125,8 +124,6 @@ def _link(
+         always_link = False
+     if link_artifact_name_suffix == _UNBOUND:
+         link_artifact_name_suffix = ""
+-    if main_output == _UNBOUND:
+-        main_output = None
+     if use_shareable_artifact_factory == _UNBOUND:
+         use_shareable_artifact_factory = False
+     if build_config == _UNBOUND: