When you have multiple types of the same boost library installed (e.g. release, debug), CMake ends up with lists of the form "optimized;lib"debug;lib-d" which we directly output to the pkgconfig files. Pkgconfig can't deal with this when it reads the list back in (ie when OCL reads in RTT's pkgconfig file).

This fixes more instances of this.

NB you may want to rename the function, and move it to a more appropriate file. I did not go looking for more instances of this, so we may end up doing this again in the future.

Tested on Mac OS X with and without multiple library types.

Stephen