Added clean rule.
Added machine-readable map file output (via -N)
Revert "use $(prefix) instead of $(DESTDIR)"

This reverts commit 61013d067bf6dff9a02e63c632ac014a04c61404.

$(prefix) and $(DESTDIR) have different meanings. We're performing
a staged install, so $(DESTDIR) makes more sense.
respect  when installing
use .exe-suffix when building on Windows
Merge remote-tracking branch 'deplinenoise/master' into HEAD