IssueTracker

The *64 interfaces, such as fstat64, off64_t, etc, are legacy interfaces created at a time when 64-bit file support was still new. They are generally exposed when defining a macro named _LARGEFILE64_SOURCE, as e.g. the glibc docs0 say.

The modern way to utilise largefile support, is to continue to use the regular interfaces (off_t, fstat, ..), and define _FILE_OFFSET_BITS=64.

This fixes the build against musl libc, ever since musl dropped the *64 compat from interfaces by default1 just for _GNU_SOURCE, unless _LARGEFILE64_SOURCE is defined. However, there are plans for a future removal of the whole *64 header API, and that workaround (adding another define) might cease to exist.