Thanks go to (in temporal order, newer to older):

Leah Neukirchen, for build, configure, testing, and various suggestions
Sijmen J. Mulder, for catching residual bashisms in configure.ac
Rafael Laboissiere, for several compatibility, correctness, test and build fixes and reports
Martin Klaiber, for pointing out problems and testing
Mohammed Isam, for having provided PCX reading support
Matthieu Crapet, for enabling out-of-tree builds
Marco Barbàra, for testing and critiques
Vitaly Minko, for testing and debugging on ARM
Damiano Biagioli, for early testing
Marta Carbone, for early testing and debugging