Generate pkgIndex.tcl

We build a small utility makePkgIndex executable which includes version.h
so it can correctly print the package name and version.

Usage: makePkgIndex <templace file> > pkgIndex.tcl

This currently produces this output:

1. Package index for rabbitmq
   
   package ifneeded rabbitmq 0.1.0 \ [list load [file join [list $dir] rabbitmq[info sharedlibextension]]]