This replaces all calls to SDL_free with a new macro, VVV_free, that
nulls the pointer afterwards. This mitigates any use-after-frees and
also completely eliminates double-frees. The same is done for any
function to free specific objects such as SDL_FreeSurface, with the
VVV_freefunc macro.
No exceptions for any of these calls, even if the pointer is discarded
or zeroed afterwards anyway. Better safe than sorry.
This is a macro rather than a function that takes in a
pointer-to-pointer because such a function would have type issues that
require casting and that's just not safe.
Even though SDL_free and other SDL functions already check for NULL, the
macro has a NULL check for other functions that don't. For example,
FAudioVoice_DestroyVoice does not check for NULL.
FILESYSTEM_freeMemory has been axed in favor of VVV_free because it
functionally does the same thing except for `unsigned char*` only.
This commit adds a new string formatting system to replace uses of
`SDL_snprintf` and string concatenation.
Making our own string formatting system has been briefly discussed
during the review of the localization branch, and on the VVVVVV
Discord. It's inspired by Python's format strings, but simpler.
This is primarily to benefit localization - strings will be easier to
understand (`Now using %s Tileset` → `Now using {area} Tileset`,
`"%s remain"` → `"{n_crewmates|wordy} remain"`), translators can change
the word order for their language's grammar (`%1$s` is a POSIX
extension), and this system is also less error-prone (making the format
string not align with the actual arguments won't result in a crash or
UB).
It also integrates our needs better - particularly the "wordy" numbers
without having to have a `help.number_words(n).c_str()` at the
callsite, translators can opt in and out of wordy numbers per string,
and this should also make it easier to solve #859.
This commit adds the formatting system itself, and changes one
`SDL_snprintf` in the code to use it as a small demo (the rest should
probably be done in the localization branch to avoid more unneeded
work).
The system is described in full detail in VFormat.h and in the pull
request description.
