Fast and simple hash table for static data

[marcov]

Another way is to recompile the entire FPC, which takes a very long time.

To put some numbers in the mix: I've a mid level machine (Ryzen 5700) and on Windows it compiles in about 1min 30s, and on Linux just over a minute.

If I'm developing a package, I mostly do a full build, and install it, but then in the 3.3.1 units directory I remove (delete or move away) the corresponding directory (rtl-generics in your case), and then I just run either local make in the package rtl-generics directory or develop using lazarus with my test progams in the src directory.

Note before switching back to normal builds it might be beneficial to clean the package dir of .o and .ppu files that are not in the units/ directory. It also assumes your program to test doesn't use any packages that depend on rtl-generics themselves.