isolate changes, keep orignal musl sources clean.
Signed-off-by: NCaoruihong <crh.cao@huawei.com>
Change-Id: Id7f3a5109771f93d397e30febba36e09ddaf4f36

Description:add unsupport api print
Team: OTHERS
Feature or Bugfix:Feature
Binary Source:No
PrivateCode(Yes/No):No

Change-Id: If54639f876c6c6d546f36f65a83e3d4ae94a58f0
Reviewed-on: http://mgit-tm.rnd.huawei.com/10522043Tested-by: Npublic jenkins <public_jenkins@notesmail.huawei.com>
Reviewed-by: Ncaoruihong 00546070 <crh.cao@huawei.com>
Reviewed-by: Nshenwei 00579521 <denny.shenwei@huawei.com>

the LFS64 macro was not self-documenting and barely saved any
characters. simply use weak_alias directly so that it's clear what's
being done, and doesn't depend on a header to provide a strange macro.

the main aim of this patch is to ensure that if not all fields are
filled in, they contain zeros, so as not to confuse applications.
reportedly some older kernels, including commonly used openvz kernels,
lack the f_flags field, resulting in applications reading random junk
as the mount flags; the common symptom seems to be wrongly considering
the filesystem to be mounted read-only and refusing to operate. glibc
has some amazingly ugly fallback code to get the mount flags for old
kernels, but having them really is not that important anyway; what
matters most is not presenting incorrect flags to the application.

I have also aimed to fill in some fields of statvfs that were
previously missing, and added code to explicitly zero the reserved
space at the end of the structure, which will make things easier in
the future if this space someday needs to be used.

to deal with the fact that the public headers may be used with pre-c99
compilers, __restrict is used in place of restrict, and defined
appropriately for any supported compiler. we also avoid the form
[restrict] since older versions of gcc rejected it due to a bug in the
original c99 standard, and instead use the form *restrict.

at the same time, make struct statfs match the traditional definition
and make it more useful, especially the fsid_t stuff.