[project @ 2001-10-23 14:34:24 by rrt]

[project @ 2001-10-23 14:34:24 by rrt]
Add rules for building and installing documentation. The story is as
follows:

GhcDocWays is set to a list of ways to build SGML docs (typically in
build.mk; it defaults to empty).
SGML_DOC = foo causes foo to be built for each way.
SGML_INSTALL_DOCS are then installed for each way;
INSTALL_DOCS are just taken as literal filenames.
make install-docs causes documents to be installed.

Also some other clearups:

Use $(if ...) where a comment lamented its non-existence.
Remove a comment about a "weird" use of exit which has vanished.