Allow linking of cygwin libraries

This patch is in the cygwin package as part of pl-CYG11-5101-no-bs.patch
since 5.10

Linking to cygwin dlls need no import library as on Windows and the
generated library names contain no lib prefix

E.g. it fixes [CPAN #69112] for Devel::Declare -lCheck not found.

Signed-off-by: Chris 'BinGOs' Williams <chris@bingosnet.co.uk>