Packaging reST documentation


All LLVM HTML documents have been converted to reST. This uncovered
an issue with 'make install', which installs only *.html files and
completely ignores *.rst (it does not invoke Sphinx to process reST).

In order to unbreak 'make install', I checked in a Dummy.html file in
r170126 to allow 'make install' to proceed.

We need some way to integrate normal 'make install' with Sphinx so
that reST documents are processed and packaged. This will introduce a
(possibly unwanted) dependency on Sphinx for normal installations,
that's why I started this discussion.

@Pawel: CC'ing you since we have this issue in 3.2, too. All *.rst
files are ignored and not packaged.


Why not just conditionally process and install the Sphinx files if sphinx-build is found, and not install the documentation if sphinx-build is not found (perhaps with a warning after configuring)?