Initial bzlmod support (#839)

foreign_cc/extensions.bzl

@@ -0,0 +1,8 @@
+"""Entry point for extensions used by bzlmod."""
+
+load("//foreign_cc:repositories.bzl", "rules_foreign_cc_dependencies")
+
+def _init(module_ctx):
+    rules_foreign_cc_dependencies(register_toolchains = False, register_preinstalled_tools = False)
+
+ext = module_extension(implementation = _init)

foreign_cc/private/framework/toolchain.bzl

@@ -86,8 +86,12 @@ framework_toolchain_repository = repository_rule(
 )
 
 # buildifier: disable=unnamed-macro
-def register_framework_toolchains():
-    """Define and register the foreign_cc framework toolchains"""
+def register_framework_toolchains(register_toolchains = True):
+    """Define and register the foreign_cc framework toolchains
+
+    Args:
+        register_toolchains: Whether to call native.register_toolchains or not
+    """
     toolchains = []
 
     for item in TOOLCHAIN_MAPPINGS:
@@ -103,4 +107,5 @@ def register_framework_toolchains():
 
         toolchains.append("@{}//:toolchain".format(toolchain_name))
 
-    native.register_toolchains(*toolchains)
+    if (register_toolchains):
+        native.register_toolchains(*toolchains)

foreign_cc/repositories.bzl

@@ -13,7 +13,8 @@ def rules_foreign_cc_dependencies(
         make_version = "4.3",
         ninja_version = "1.10.2",
         register_preinstalled_tools = True,
-        register_built_tools = True):
+        register_built_tools = True,
+        register_toolchains = True):
     """Call this function from the WORKSPACE file to initialize rules_foreign_cc \
     dependencies and let neccesary code generation happen \
     (Code generation is needed to support different variants of the C++ Starlark API.).
@@ -41,11 +42,14 @@ def rules_foreign_cc_dependencies(
             installed on the exec host
 
         register_built_tools: If true, toolchains that build the tools from source are registered
+
+        register_toolchains: If true, registers the toolchains via native.register_toolchains. Used by bzlmod
     """
 
-    register_framework_toolchains()
+    register_framework_toolchains(register_toolchains = register_toolchains)
 
-    native.register_toolchains(*native_tools_toolchains)
+    if (register_toolchains):
+        native.register_toolchains(*native_tools_toolchains)
 
     native.register_toolchains(
         str(Label("//toolchains:preinstalled_autoconf_toolchain")),
@@ -55,13 +59,14 @@ def rules_foreign_cc_dependencies(
     )
 
     if register_default_tools:
-        prebuilt_toolchains(cmake_version, ninja_version)
+        prebuilt_toolchains(cmake_version, ninja_version, register_toolchains)
 
     if register_built_tools:
         built_toolchains(
             cmake_version = cmake_version,
             make_version = make_version,
             ninja_version = ninja_version,
+            register_toolchains = register_toolchains,
         )
 
     if register_preinstalled_tools:

toolchains/built_toolchains.bzl

@@ -24,16 +24,17 @@ _CMAKE_SRCS = {
 }
 
 # buildifier: disable=unnamed-macro
-def built_toolchains(cmake_version, make_version, ninja_version):
+def built_toolchains(cmake_version, make_version, ninja_version, register_toolchains):
     """Register toolchains for built tools that will be built from source"""
-    _cmake_toolchain(cmake_version)
-    _make_toolchain(make_version)
-    _ninja_toolchain(ninja_version)
-
-def _cmake_toolchain(version):
-    native.register_toolchains(
-        "@rules_foreign_cc//toolchains:built_cmake_toolchain",
-    )
+    _cmake_toolchain(cmake_version, register_toolchains)
+    _make_toolchain(make_version, register_toolchains)
+    _ninja_toolchain(ninja_version, register_toolchains)
+
+def _cmake_toolchain(version, register_toolchains):
+    if register_toolchains:
+        native.register_toolchains(
+            "@rules_foreign_cc//toolchains:built_cmake_toolchain",
+        )
 
     if _CMAKE_SRCS.get(version):
         cmake_meta = _CMAKE_SRCS[version]
@@ -403,16 +404,17 @@ def _cmake_toolchain(version):
 
     fail("Unsupported cmake version: " + str(version))
 
-def _make_toolchain(version):
-    native.register_toolchains(
-        "@rules_foreign_cc//toolchains:built_make_toolchain",
-    )
+def _make_toolchain(version, register_toolchains):
+    if register_toolchains:
+        native.register_toolchains(
+            "@rules_foreign_cc//toolchains:built_make_toolchain",
+        )
     if version == "4.3":
         maybe(
             http_archive,
             name = "gnumake_src",
             build_file_content = _ALL_CONTENT,
-            patches = ["@rules_foreign_cc//toolchains:make-reproducible-bootstrap.patch"],
+            patches = [str(Label("//toolchains:make-reproducible-bootstrap.patch"))],
             sha256 = "e05fdde47c5f7ca45cb697e973894ff4f5d79e13b750ed57d7b66d8defc78e19",
             strip_prefix = "make-4.3",
             urls = [
@@ -424,10 +426,11 @@ def _make_toolchain(version):
 
     fail("Unsupported make version: " + str(version))
 
-def _ninja_toolchain(version):
-    native.register_toolchains(
-        "@rules_foreign_cc//toolchains:built_ninja_toolchain",
-    )
+def _ninja_toolchain(version, register_toolchains):
+    if register_toolchains:
+        native.register_toolchains(
+            "@rules_foreign_cc//toolchains:built_ninja_toolchain",
+        )
     if version == "1.10.2":
         maybe(
             http_archive,