NB: This commit renames some files.  In each of your build directories,
    you will need to:

	rm -f ghc/compiler/prelude/primops.txt
	rm -f ghc/compiler/prelude/primops.i
	rm -f ghc/lib/std/PrelGHC.hi-boot
	lndir ../fptools	# or wherever your CVS working directory is

The change:
Run PrelGHC.hi-boot through the preprocesor, as we already do primops.txt.

This commit introduces a new prefix, ".pp", which means "run through
preprocesor".  In a previous commit, I changed ghc/compiler/Makefile
to preprocess primops.txt into primops.i.  That is gone now.  We now
preprocess primops.txt.pp (a file in the CVS repository) into primops.txt
(a platform-dependent file, created at build time).  We also preprocess
PrelGHC.hi-boot.pp (a file in the CVS repository) into PrelGHC.hi-boot
(a platform-dependent file, created at build time).

The reason for using the preprocessor is because fewer primops are defined
if SUPPORT_LONG_LONGS is undefined.  SUPPORT_LONG_LONGS is undefined on
64-bit architectures such as the Alpha.