Here's the patch for this:
https://github.com/soundradix/JUCE/commit/ead40576760b8737cfdf70a19c6050a2ad4b14c4
(EDIT: fixed patch)
Introjucer uses the appropriate libAAXLibrary and libPluginLibrary _libcpp.a versions as necessary.
The RTAS SDK, unlinke the AAX SDK, does not have the libcpp configuration out of the box, but one should be created to be similar to the AAX SDK.
Cheers, Yair