fix: support debian multiarch with local toolchains

Author: rickeylev

python/private/get_local_runtime_info.py

@@ -45,6 +45,11 @@
     # The platform-specific filename suffix for library files.
     # Includes the dot, e.g. `.so`
     "SHLIB_SUFFIX",
+    # Debian has a "multiarch" layout that has libs for different archs
+    # in slightly other locations. The MULTIARCH sysconfig varible tells
+    # which directory under `LIBDIR` these exist in, if any.
+    # See https://wiki.debian.org/Python/MultiArch
+    "MULTIARCH",
 ]
 data.update(zip(config_vars, sysconfig.get_config_vars(*config_vars)))
 print(json.dumps(data))

python/private/local_runtime_repo.bzl

@@ -126,6 +126,7 @@ def _local_runtime_repo_impl(rctx):
     # In some cases, the same value is returned for multiple keys. Not clear why.
     shared_lib_names = {v: None for v in shared_lib_names}.keys()
     shared_lib_dir = info["LIBDIR"]
+    multiarch = info["MULTIARCH"]
 
     # The specific files are symlinked instead of the whole directory
     # because it can point to a directory that has more than just
@@ -141,6 +142,11 @@ def _local_runtime_repo_impl(rctx):
             repo_utils.watch(rctx, origin)
             rctx.symlink(origin, "lib/" + name)
 
+        origin_multiarch = rctx.path("{}/{}/{}".format(shared_lib_dir, multiarch, name))
+        if origin_multiarch.exists:
+            repo_utils.watch(rctx, origin)
+            rctx.symlink(origin, "lib/{}/{}".format(multiarch, name))
+
     rctx.file("WORKSPACE", "")
     rctx.file("MODULE.bazel", "")
     rctx.file("REPO.bazel", "")