1.0: Remove lfs64 API (open64 and similar) #4805
Description
With 1.0 we will default to 64-bit time_t and off_t, and users will need to opt in to 32-bit versions of these APIs - if we expose them at all. This means the API like open64 will be redundant with open. There isn't a reason to use both unless a user opts in to 32-bit off_t but occasionally needs to use 64-bit operations: this doesn't sound like a usecase worth supporting. They also aren't posix.
To back this up, it sounds like musl would deprecate them if they could.
-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE have nothing to do with supporting large files properly but with exposing the idiotic legacy interfaces with 64 on the end of their names (like open64, lseek64, etc.). only -D_FILE_OFFSET_BITS=64 should ever be used, anywhere, even on glibc.