Since we switched from autotools to Meson in commit
94592c14, we don't need to include
`config.h` early to properly enable large file support.  Meson passes
the required macros on the compiler command line instead of defining
them in `config.h`.

This means we can include `config.h` at any time, whenever we want to
check its macros, and there are no ordering constraints.

This eliminates some overhead, because the compiler doesn't need to
consider these functions throwing.

Prepare for ID3 support on userspace NFS/SMB/CIFS mounts.

Use a 128 byte buffer instead of reading 10 bytes first and then 118.

Copy the query buffer to the allocated buffer, and read only the
remaining data.