SDL_REVISION should have a SDL- (or maybe SDL3-) prefix #14114
Description
When we added SDL_REVISION in SDL 2, one of its purposes was to be able to identify the age and vendor of an unknown SDL binary vendored into a game by using the distinctive SDL- prefix, like this:
$ strings libSDL2-2.0.so.0 | grep SDL-
SDL-release-2.32.10-0-g5d2495703 (Debian 2.32.10+dfsg-4)
In SDL2 this still works as intended: in formal releases, SDL_SOURCE_VERSION is set to the contents of REVISION.txt and then a SDL- prefix is added, or when getting the version number from git, it's similarly always prefixed with SDL-.
But this doesn't currently work for SDL 3: in formal releases, REVISION.txt looks like release-3.2.22-0-ga96677bdf (no SDL- prefix) and setting SDL_REVISION doesn't add the prefix either. When getting the version number from git, it's now prefixed with SDL3- instead. (I think this did work in the early SDL 3 preview releases, though.)
I think it would be better if SDL3 used a SDL- prefix, the same as SDL 2. We can tell it's SDL 3 by the version number and the SONAME, and it's easier to only have one prefix to search for.
The documentation still mentions a SDL- prefix.