Use ppkg-config instead of pkg-config

This is my little wrapper for pkg-config that I usually use.  It
doesn't actually have any effect if you don't use the optional
features.
Support building without talloc

My simple built script now actually supports detecting libtalloc
(using pkg-config) and conditionally compiling it in.
Rename upconfigure -> build

Naming this "build" makes it a little more apparent what it's actually
doing.