Details, please. How do I do that?
readelf -aW /lib/libc.so.6 | grep epoll
if the symbols are declared WEAK then you can do this (assuming AJ agrees).
#pragma weak epoll_whatever
should do the trick.
In the resulting binary "readelf -aW mybinary | grep epoll" should should you the weak linkage. At runtime:
if (epoll_foobar) { ... it's safe to use }