rules/ remove run_under

rules/ were never meant to be added to the release. Now that we are not
*running* multi-arch binaries, we can remove the infrastructure that was
necessary to do so.

I may get back to this -- but we need to dust quite a bit off before
that happens.

ci/test

@@ -17,7 +17,7 @@ tools/bazel build "$@" \
     --experimental_use_hermetic_linux_sandbox \
     --sandbox_writable_path="$cache_prefix" \
     --sandbox_add_mount_pair=/proc \
-    //test/c:which_libc_linux_amd64_gnu.2.19
+    //test/c:which_libc
 
 # then test everything else with the standard sandbox
 echo "--- bazel test $* ..."

rules/platform.bzl

@@ -1,12 +1,7 @@
 # Copyright 2023 Uber Technologies, Inc.
 # Licensed under the MIT License
 
-def _vars_script(env, run_under, cmd):
-    ret = ["#!/bin/sh"]
-    for k, v in env.items():
-        ret += ['export {}="{}"'.format(k, v)]
-    ret += ['exec {} {} "$@"'.format(run_under, cmd)]
-    return "\n".join(ret) + "\n"  # trailing newline is easier on the eyes
+load("@bazel_skylib//lib:paths.bzl", "paths")
 
 def _platform_transition_impl(settings, attr):
     _ignore = settings
@@ -23,22 +18,18 @@ _platform_transition = transition(
 )
 
 def _platform_binary_impl(ctx):
-    source_info = ctx.attr.src[DefaultInfo]
-
-    executable = None
-    if source_info.files_to_run and source_info.files_to_run.executable:
-        command = _vars_script(ctx.attr.env, ctx.attr.run_under, source_info.files_to_run.executable.short_path)
-        executable = ctx.actions.declare_file("{}_{}".format(ctx.file.src.basename, ctx.attr.platform))
-        ctx.actions.write(
-            output = executable,
-            content = command,
-            is_executable = True,
+    platform_sanitized = ctx.attr.platform.replace("/", "_").replace(":", "_")
+    dst = ctx.actions.declare_file("{}-{}".format(paths.basename(ctx.file.src.path), platform_sanitized))
+    src = ctx.file.src
+    ctx.actions.run_shell(
+        outputs = [dst],
+        inputs = [src],
+        command = "cp $1 $2",
+        arguments = [src.path, dst.path],
     )
-
     return [DefaultInfo(
-        executable = executable,
-        files = depset([executable]),
-        runfiles = ctx.runfiles(files = ctx.files.src),
+        files = depset([dst]),
+        executable = dst,
     )]
 
 _attrs = {
@@ -50,12 +41,6 @@ _attrs = {
     "platform": attr.string(
         doc = "The platform to build the target for.",
     ),
-    "run_under": attr.string(
-        doc = "wrapper executable",
-    ),
-    "env": attr.string_dict(
-        doc = "Environment variables for the test",
-    ),
     "_allowlist_function_transition": attr.label(
         default = "@bazel_tools//tools/allowlists/function_transition_allowlist",
     ),

test/windows/BUILD

@@ -9,15 +9,6 @@ cc_binary(
     tags = ["manual"],
 )
 
-# TODO(motiejus): bring back windows tests, not only builds
-#platform_test(
-#    name = "winver_windows_amd64",
-#    src = "winver",
-#    platform = "//platform:windows_amd64",
-#    run_under = "wine64-stable",
-#    tags = ["no-sandbox"],
-#)
-
 platform_binary(
     name = "winver_windows_amd64",
     src = "winver",