My experimental build with clang-cl at -Wall did show up a few things
that are safe enough to fix right now. One was this list of missing
includes, which was causing a lot of -Wmissing-prototype warnings, and
is a real risk because it means the declarations in headers weren't
being type-checked against the actual function definitions.
Happily, no actual mismatches.
Correcting a source file name in the docs just now reminded me that
I've seen a lot of outdated source file names elsewhere in the code,
due to all the reorganisation since we moved to cmake. Here's a giant
pass of trying to make them all accurate again.
This gets rid of all those annoying 'win', 'ux' and 'gtk' prefixes
which made filenames annoying to type and to tab-complete. Also, as
with my other recent renaming sprees, I've taken the opportunity to
expand and clarify some of the names so that they're not such cryptic
abbreviations.
