In the past few days I went through an unfair amount of pain with building plugins in Mavericks and here I share some experiences so others wont suffer.
If you are going to make platform-independent plugin, by way of using gcc, please consider few notes. First, gcc that comes with XCode 5 on mavericks, is only a front end and at the backend, it is still CLang. If you want to use gcc, you need to build it by yourself (e.g. via brew).
Secondly, until OS X 10.8 the default binaries for std library was libstdc++ but since mavericks it is changed to libc++. You need to explicitly tell to gcc to use the former or, simply use g++ instead.
I also suggest V-Rep development team to modify the Makefile and Skeleton related to c++ plugins as its current state will fail on either linux or mac.
It is still missing from the latest source files VREP 3.2.1 (both meshCalculationPlugin and pathPlanningPlugin).
After adding the header mentioned, everything is fine.
Cheers,