sys/compat: Don't clobber f_oflags with zero.

Mistake was introduced in previous refactoring.

don't overallocate (follows similar change to compat/sys/statvfs.h)

Ignore the supplied size, and always use the argument size that we know.
Found by maxv@

Yet another idiotic compat syscall that was developed with literally zero
test made. Simply invoking this syscall with _valid parameters_ triggers a
fatal fault, because the kernel tries to write to

Yet another idiotic compat syscall that was developed with literally zero
test made. Simply invoking this syscall with _valid parameters_ triggers a
fatal fault, because the kernel tries to write to userland addresses.

With specially-crafted parameters it is easy to completely escalate
privileges into the kernel.

Also the size of the allocation is just obviously wrong, but it looks like
the callers are even more wrong, so not gonna fix it for now.

Reported-by: syzbot+b05096f3114b2820d81c@syzkaller.appspotmail.com

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deduplicate the conversion function from statvfs -> statfs12

prefix compat with __ in case __dso_hidden is not available

avoid linker warning for compat symbols that are used internally in libc,
by introducing a hidden compat_foo() function, using that internally in
libc, and exposing foo as a strong alias to compat_fo

avoid linker warning for compat symbols that are used internally in libc,
by introducing a hidden compat_foo() function, using that internally in
libc, and exposing foo as a strong alias to compat_foo(). I am open for
better ideas.

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merge christos-time_t

MFSNAMELEN only belongs in compat.

whitespace.

Make filehandles opaque to userland

Fix alignement problems for fhandle_t, exposed by gcc4.1.

While touching all vptofh/fhtovp functions, get rid of VFS_MAXFIDSIZ,
version the getfh(2) syscall and explicitly pass the size available in

Fix alignement problems for fhandle_t, exposed by gcc4.1.

While touching all vptofh/fhtovp functions, get rid of VFS_MAXFIDSIZ,
version the getfh(2) syscall and explicitly pass the size available in
the filehandle from userland.

Discussed on tech-kern, with lots of help from yamt (thanks!).

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update for fhstat.

merge ktrace-lwp.

compat code reorg.