Switch to using :port

BUILD

@@ -77,7 +77,7 @@ cc_library(
         "upb/port_def.inc",
         "upb/port_undef.inc",
     ],
-    visibility = ["//tests:__pkg__"],
+    visibility = ["//:__subpackages__"],
 )
 
 cc_library(

upb/util/BUILD

@@ -14,7 +14,7 @@ cc_library(
     hdrs = ["def_to_proto.h"],
     visibility = ["//visibility:public"],
     deps = [
-        "//:generated_code_support__only_for_generated_code_do_not_use__i_give_permission_to_break_me",
+        "//:port",
         "//:reflection",
     ],
 )
@@ -61,7 +61,7 @@ cc_library(
     hdrs = ["required_fields.h"],
     visibility = ["//visibility:public"],
     deps = [
-        "//:generated_code_support__only_for_generated_code_do_not_use__i_give_permission_to_break_me",
+        "//:port",
         "//:reflection",
     ],
 )
@@ -104,7 +104,7 @@ cc_library(
     hdrs = ["compare.h"],
     visibility = ["//visibility:public"],
     deps = [
-        "//:generated_code_support__only_for_generated_code_do_not_use__i_give_permission_to_break_me",
+        "//:port",
         "//:reflection",
     ],
 )