Reduce glibc dependences in drrun to operate on older distros

While the core libdynamorio.so has no library dependences, drrun does. Building drrun on a more recent machine and then running on something older like Debian 11 (glibc 2.31) results in:

/build_a64_rel/bin64/drrun: /lib/aarch64-linux-gnu/libc.so.6: version `GLIBC_2.33' not found (required by /build_a64_rel/bin64/drrun)

This issue covers trying to improve binary interoperability of drrun.