Generating different name with different architecture and with the same version of python is not ideal. pkgconfig files should be architecture independent and libraries for different architectures are stored in different directories. Therefore it will be simpler to remove architecture from names /usr/lib64/pkgconfig/pyldb-util.cpython-36m-x86_64-linux-gnu.pc vs. /usr/lib64/pkgconfig/pyldb-util36.pc
*** This bug has been marked as a duplicate of bug 12901 ***
This will hopefully be fixed in ldb-1.2.2, but that's needs more discussion on the mailing list first.