Prior to this commit, -module was not respected when the specified
output name happened to end with the platform's shared library
suffix. In addition, the logic for generating shared libraries
with -module in effect has been incomplete and partially also
incorrect.
Its development history notwithstanding, the pronounced goals of
slibtools have always included support of all reasonably modern,
reasonably posix-compliant systems and cross-targets. This commit
thus makes the distinction between 'part of the midipix framework'
and 'created by the framework's lead developer' both clearer and
more visible.
