find_library_file doesn't handle openbsd shared library naming scheme

[sthen]

distutils/distutils/compilers/C/unix.py

Line 403 in 603b94e

def find_library_file(self, dirs, lib, debug=False):

OpenBSD shared libraries are just installed as lib.so.., there are no symlinks from lib.so. The code in find_library_path only searches for .so without version numbers and .a, so it fails to find these unless there's also an associated static library.

(We found this after looking at issues with Pillow not building support for some image formats after updates to the various libraries which they depend on removed static libraries).