under -Dusedl there are no warnings about the other dl_ functions

under -Dusedl there are no warnings about the other dl_ functions

without usedl, the warnings are like:

Subroutine DynaLoader::dl_error redefined at (eval 1) line 2
... warnings about every other DynaLoader function
Subroutine DynaLoader::dl_error redefined at (eval 2) line 2

with usedl, only dl_error is defined, so the other warnings disappear,
since the regexp expected two new-lines between the dl_error warnings
the test failed.

The change makes one of the newlines optional.