Run original make also for diagnostics

If you run make with -n switch, it would just print the forwarding
command. Now it should continue into the original make, having that
one printing its actions as well.
Only start parallel make if user hasn't already

The -j flag should only be submitted once. If we are enclosed by yet
another layer of makes, then it will have setup everything for this
sub-make to take part in the job pool.
Explicitly specify language for precompiled headers

This will hopefully guide some (buggy) compiler variants to not start
interpreting the header as a full program, or at least give a more
sensible error message.
Output the name of the libtool archive generated

Enables us to take of this file in a custom clean rule.
Clean extra files that has been added to configure
Remove hardcoded project names and directories

Everything is now set through variables, which means that we can
change the name of the project by just altering the header.
Don't distinguish between target and project variables

Since the project is only building one main target, the library, and
the other targets are just auxiliaries, then the distinction becomes
confusing and unnecessary.