Depend on upb_generator:mangle from rust compiler

Update cmake to include necessary upb_generator files and upb namespace.

PiperOrigin-RevId: 595144470

CMakeLists.txt

@@ -279,6 +279,8 @@ endif (MSVC)
 include_directories(
   ${ZLIB_INCLUDE_DIRECTORIES}
   ${protobuf_BINARY_DIR}
+  # Support #include-ing other top-level directories, i.e. upb_generator.
+  ${protobuf_SOURCE_DIR}
   ${protobuf_SOURCE_DIR}/src)
 
 set(protobuf_ABSL_PROVIDER "module" CACHE STRING "Provider of absl library")

src/google/protobuf/compiler/rust/BUILD.bazel

@@ -44,6 +44,7 @@ cc_library(
         ":oneof",
         "//src/google/protobuf:protobuf_nowkt",
         "//src/google/protobuf/compiler/cpp:names",
+        "//upb_generator:mangle",
         "@com_google_absl//absl/log:absl_check",
         "@com_google_absl//absl/log:absl_log",
     ],

src/libprotoc.map

@@ -3,6 +3,7 @@
     extern "C++" {
       *google*;
       pb::*;
+      upb::*;
     };
     scc_info_*;
     descriptor_table_*;