There should be absolutely no code change semantic in this commit. If
there is, that's a mistake and it's on me. I only cleaned up the syntax
in the C file which basically was following none of GIMP coding style
(tabs everywhere, brackets at end of lines, nearly no space anywhere so
all the code was a compressed mess which was hard to read, indentation
absolutely wrong everywhere, etc.).
I cleaned it up with a bunch of regexp search-and-replace followed by a
lot of manual cleaning and verification as well.

I also tested with various FLI files found on the web, and they were
loading fine in GIMP. So I believe/hope that I didn't mess up somewhere,
but it looks as the cleaning went all fine.