IPA_Emulation: Make dependencies to RSL/MGCP/SCCP/GSUP conditional

Let's use the preprocessor to avoid IPA_Emulation pulling *all*
dependencies into each and any of our projects.  The code readability
suffers a bit from the many #ifdefs, but compilation speed increases
if we don't have to pull in all those (recursive) dependencies.

After all, a BTS test case will never need SCCP, GSUP or MGCP.

Change-Id: Ic0231adbd2171214de133d26b3fbf36130ee8aa0
16 files changed