check for rpmlib version

[oliverkurth]

Is there a way to check at compile time for the rpmlib version?

In this particular case I want to use the enum value RPMTRANS_FLAG_NODB of enum rpmtransFlags_e in include/rpm/rpmts.h, but stay compatible with older versions that do not have this implemented. Since it's an enum, I cannot use #ifdef. So alternatively I thought I can use a macro that lets me check the version of rpmlib.