We were installing every readable file in man/man3, but
only unstalling files matching opus_*.3. Some doxygen
versions construct manpage versions of the marked up
header files and directory index, which got left on the
system after 'make uninstall'.
I don't think the 'uninstall' target is widely used, it's
often broken and can easily break other software. However,
we rely on 'make distcheck' which does verify this issue.
Instead, only install the opus_*.3 manpages, which are the
core api documentation.
And explicitly specify what we want included in EXTRA_DIST of doc/Makefile.am,
otherwise make dist picks up whatever random junk you might have laying around
in that dir at the time you run it.
Tweak the top level delegation targets, because this means distclean will be
run in the doc dir by default now without our help.
Doxygen is a tool for generating programming documentation
based on comments in header and source files. This commit
adds the necessary configuration file and associated support
in the autotools build.
Right now it doesn't generate much documentation because our
public header files aren't marked up. Warnings are printed
for undocumented members and arguments.
