Refusing the platform's CSPRNG for such nonsense reasons is perhaps the dumbest form of POSIX worship. This is obviously an area where platform feature detection makes sense, there's no reason to follow a religion of standards adherence when it directly leads you into harm's way
Not POSIX/C99 worship as much as the very practical issue that a lot of C code which used to compile just fine stopped compiling once compilers defaulted to using C23. To use POSIX calls while compiling with -std=c99 (so I don’t have to update my code should C29 or what not come out) one needs to declare, for each .c file which uses a POSIX call, the version of POSIX the C file is compatible with.
