This is very mature, stable, small-footprint code with minimal dependencies (suitable for use in embedded deployments) that needs only occasional very minor bugfixes. Test reports from odd platforms and better regression tests are particularly welcome. Don't try to redesign it, applications beyond counting would break if you did.
It's "GIFLIB" in caps as a nod to the code's origins in the dark and backward abysm of MS-DOS, but Unix hackers are encouraged to spell it "giflib" in deference to local conventions. :-)