Packages ending in -dev: just assume that the originating aport has the
same pkgname, except for the -dev at the end. Otherwise we may end up
with the wrong package.

For example, if something depends on plasma-framework-dev, and
plasma-framework is in Alpine, but plasma is in pmaports, then the
regular guess_main() algorithm below would pick plasma instead of
plasma-framework.

Fixes: build.postmarketos.org#52