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