curl: Disable symbol hiding logic in build for CMake

We already disable the code using `HIDES_CURL_PRIVATE_SYMBOLS`, so skip
the code to set it too, thus avoiding unnecessary `message()` calls.

Utilities/cmcurl/CMakeLists.txt

@@ -183,7 +183,9 @@ if(MSVC)
   mark_as_advanced(BUILD_RELEASE_DEBUG_DIRS)
 endif()
 
+if(0) # This code not needed for building within CMake.
 include(CurlSymbolHiding)
+endif()
 
 option(HTTP_ONLY "disables all protocols except HTTP (This overrides all CURL_DISABLE_* options)" OFF)
 mark_as_advanced(HTTP_ONLY)