solarish update stat type with st_fstype field.

ref illumos: https://illumos.org/man/2/stat
ref solaris: https://docs.oracle.com/cd/E36784_01/html/E36872/stat-2.html

Author: devnexen

libc-test/semver/solarish.txt

@@ -17,6 +17,7 @@ LIO_WRITE
 PIPE_BUF
 SIGEV_PORT
 _POSIX_VDISABLE
+_ST_FSTYPSZ
 aio_cancel
 aio_error
 aio_fsync

src/unix/solarish/mod.rs

@@ -338,7 +338,7 @@ s! {
         pub st_ctime_nsec: ::c_long,
         pub st_blksize: ::blksize_t,
         pub st_blocks: ::blkcnt_t,
-        __unused: [::c_char; 16],
+        pub st_fstype: [::c_char; _ST_FSTYPSZ as usize],
     }
 
     pub struct termios {
@@ -2023,6 +2023,8 @@ pub const _SC_XOPEN_STREAMS: ::c_int = 761;
 pub const _SC_IPV6: ::c_int = 762;
 pub const _SC_RAW_SOCKETS: ::c_int = 763;
 
+pub const _ST_FSTYPSZ: ::c_int = 16;
+
 pub const _MUTEX_MAGIC: u16 = 0x4d58; // MX
 pub const _COND_MAGIC: u16 = 0x4356; // CV
 pub const _RWL_MAGIC: u16 = 0x5257; // RW