Revert "fixup! fix(toolchain): do not force users to depend on optional toolchains"

This reverts commit c914a9e.

Author: aignas

python/private/py_toolchain_suite.bzl

@@ -100,17 +100,16 @@ def py_toolchain_suite(*, prefix, user_repository_name, python_version, set_pyth
         **kwargs
     )
 
-    is_precompile_enabled = Label("//python/config_settings:is_precompile_enabled")
     native.toolchain(
         name = "{prefix}_py_exec_tools_toolchain".format(prefix = prefix),
         toolchain = "@{user_repository_name}//:py_exec_tools_toolchain".format(
             user_repository_name = user_repository_name,
         ),
         toolchain_type = EXEC_TOOLS_TOOLCHAIN_TYPE,
+        # The target settings capture the Python version
         target_settings = select({
-            # NOTE: this is equivalent to (is_precompile_enabled AND target_settings)
-            is_precompile_enabled: target_settings,
-            "//conditions:default": [is_precompile_enabled],
+            Label("//python/config_settings:is_precompile_enabled"): target_settings,
+            "//conditions:default": [Label("//python/config_settings:is_precompile_enabled")],
         }),
         exec_compatible_with = kwargs.get("target_compatible_with"),
     )