Add patch file to remove use of incompatible_use_toolchain_transition

from upb.

Part of removing the toolchain transition entirely, bazelbuild#14127.

third_party/BUILD

@@ -35,6 +35,7 @@ filegroup(
         "//third_party/py/mock:srcs",
         "//third_party/py/six:srcs",
         "//third_party/remoteapis:srcs",
+        "//third_party/upb:srcs",
         "//third_party/zlib:srcs",
     ],
 )

third_party/upb/00_remove_toolchain_transition.patch

@@ -0,0 +1,20 @@
+diff --git a/bazel/upb_proto_library.bzl b/bazel/upb_proto_library.bzl
+index cb9800ca..08d03edc 100644
+--- a/bazel/upb_proto_library.bzl
++++ b/bazel/upb_proto_library.bzl
+@@ -316,7 +316,6 @@ _upb_proto_library_aspect = aspect(
+     attr_aspects = ["deps"],
+     fragments = ["cpp"],
+     toolchains = ["@bazel_tools//tools/cpp:toolchain_type"],
+-    incompatible_use_toolchain_transition = True,
+ )
+
+ upb_proto_library = rule(
+@@ -369,7 +368,6 @@ _upb_proto_reflection_library_aspect = aspect(
+     attr_aspects = ["deps"],
+     fragments = ["cpp"],
+     toolchains = ["@bazel_tools//tools/cpp:toolchain_type"],
+-    incompatible_use_toolchain_transition = True,
+ )
+
+ upb_proto_reflection_library = rule(

third_party/upb/BUILD

@@ -0,0 +1,11 @@
+licenses(["notice"])
+
+filegroup(
+    name = "srcs",
+    srcs = glob(["**"]),  # glob everything to satisfy the compile.sh srcs test
+    visibility = ["//third_party:__pkg__"],
+)
+
+exports_files([
+    "00_remove_toolchain_transition.patch",
+])