Teach libglaze to look for wrapper library in current working directory

Previously, with libfoo.so in the current directory, the following
command would fail:

	glaze --wrapper=libfoo.so <program> <args>

And to fix things, the user would have to explicitly name the current
working directory such as:

	glaze --wrapper=./libfoo.so <program> <args>

That seems like a silly requirement, (and is an artefact if the logic
of the dynamic loader).

To allow the convenient usage (without "./") we teach libglaze to
explicitly look for the wrapper in the current working directory, and
if found, to resolve its absolute path.