fuse2fs: explicitly set _FILE_OFFSET_BITS again

fuse2fs: explicitly set _FILE_OFFSET_BITS again

In commit 3ab99d9b602, the build system was changed not to set
_FILE_OFFSET_BITS explicitly due to some weird error on mips64el.
Unfortunately, this breaks the aarch64 Debian build because libfuse
2.9.9 requires this value to be set explicitly.  Restore this dumb
preprocessor symbol dependency with even more hackery as documented in
the commit.

Fixes: 3ab99d9b602 ("Remove explicit #define of _FILE_OFFSET_BITS")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20240529181214.GA52969@frogsfrogsfrogs
Signed-off-by: Theodore Ts'o <tytso@mit.edu>