Switch to using .in files

If you're not using /opt/rt4 for testing, inline substitution is
incredibly painful and error prone.  You also always have to remember to
reset files before running 'make dist'.
Don't hardcode the system perl

Since we're updating these files to use .in files and avoid the library
churn dance, also switch to using the perl you used to run Makefile.PL
Merge branch '2.9/stop-inline-substitution' into 2.9-trunk