Revert "Copy module file instead of symlinking."

This reverts commit 578ce77.

Copying doesn't appear to help with
bazelbuild/bazel#20886,
and it's going to be fixed in Bazel 7.1 anyway.

elisp/BUILD

@@ -534,19 +534,6 @@ elisp_binary(
     ],
 )
 
-py_binary(
-    name = "copy_file",
-    srcs = ["copy_file.py"],
-    python_version = "PY3",
-    srcs_version = "PY3",
-    visibility = [
-        # FIXME: Make private once
-        # https://github.com/bazelbuild/proposals/blob/main/designs/2019-10-15-tool-visibility.md
-        # is implemented in all supported Bazel versions.
-        "//visibility:public",
-    ],
-)
-
 cc_defaults(
     name = "launcher_defaults",
     copts = LAUNCHER_COPTS,

elisp/defs.bzl

@@ -445,13 +445,10 @@ def _elisp_cc_module_impl(ctx):
         lib = out.library_to_link.dynamic_library
     else:
         lib = ctx.actions.declare_file(filename)
-        ctx.actions.run(
-            executable = ctx.executable._copy_file,
-            arguments = [ctx.actions.args().add("--").add(out.library_to_link.dynamic_library).add(lib)],
-            inputs = [out.library_to_link.dynamic_library],
-            outputs = [lib],
-            mnemonic = "Copy",
-            progress_message = "Copying %{input} to %{output}",
+        ctx.actions.symlink(
+            output = lib,
+            target_file = out.library_to_link.dynamic_library,
+            progress_message = "Creating symbolic link " + lib.short_path,
         )
 
     # Replicate some implementation details of cc_binary to make coverage work,
@@ -567,11 +564,6 @@ C/C++ compiler.  See the [corresponding attribute for
             default = Label("//elisp:module_config"),
             providers = [CcDefaultInfo, ModuleConfigInfo],
         ),
-        "_copy_file": attr.label(
-            default = Label("//elisp:copy_file"),
-            executable = True,
-            cfg = "exec",
-        ),
     },
     provides = [EmacsLispInfo],
     fragments = ["cpp"],