On Android, the label_file.c file is compiled for all platforms,
including OSX. OSX has a slightly different prototype for the
getxattr function.
ssize_t getxattr(const char *path, const char *name, void *value, size_t size, u_int32_t position, int options);
which causes a compile error when compiling libselinux on OSX.
```
external/selinux/libselinux/src/label_file.c:1038:37: error: too few arguments to function call, expected 6, have 4
read_digest, SHA1_HASH_SIZE);
^
/Applications/Xcode9.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.13.sdk/usr/include/sys/xattr.h:61:1: note: 'getxattr' declared here
ssize_t getxattr(const char *path, const char *name, void *value, size_t size, u_int32_t position, int options);
^
1 error generated.
```
On OSX builds, add the additional arguments so that the code compiles.
As both SELinux labels and the restorecon partial digest are stored in
extended attributes, it's theoretically possible that someone
could assign SELinux labels and hash digests on OSX filesystems.
Doing so would be extremely weird and completely untested, but
theoretically possible.
Signed-off-by: Nick Kralevich <nnk@google.com>
cfa868e4d3