r6177: Use here documents instead of print() statements to generate the

r6177: Use here documents instead of print() statements to generate the
Makefile fragments for the build system.  This allows the file to be
edited without using quite as many backslashes.  Some are still necessary
for interpolation of perl variables though.

I've diffed the new Makefile against the old and there are only some
extra newlines as a result of making things more consistent.
(This used to be commit 3808c5e092e1a11d453d0a043818a10e28c78961)