- use standard headers
- don't use perror, don't use sprintf
- fix time handling issues
- compile in paths so the data can be installed (from patch-ab)
- fix name conflict with libc
- avoid undefined behavior
- avoid implicit int for clang
- declare own functions, sprinkle const and static, and fix
signedness to get a clean build (except for one remaining issue
where it's not clear what to do)
- remove unused elements detected by gcc
- fix some problems detected by gcc
- fix a startup crash
- modernize the makefile
Also, don't install the raw image bitmap data and the scripts to digest
it; install only the digested form, as that's all that's used at runtime.