mapi: Teach es{1,2}api/ABI-check shared library names on Cygwin

Ideally we'd be able to get the library filename from libtool, but that
doesn't seem to be a feature...

Use of ${uname} is presumably ok here as we won't be running 'make check' if
we are cross-compiling

Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
2 files changed