Make lldb build with Makefiles on OS X.

This change does the following:

* Adds Makefile build scripts to debug server.

* Fixes a few small mistakes in the other makefiles.

* Modifies generate-vers.pl slightly to also work for debugserver.

* Changes the OS X, non-framework python search path from libdir to
  libdir/python2.X/site-packages where it is installed by the build
  system (also where it is installed on other operating systems).

Patch by Keno Fischer.