/usr/lib64/pkgconfig/libmongoc-1.0.pc contains:
Libs: -L${libdir} -lmongoc-1.0 -lsasl2 -lssl -lcrypto -lrt -lresolv -lz -lsnappy
But applications linked against libmongoc probably don't need these library.
Reported as https://bugzilla.redhat.com/1560611