Android: add some of the same LFS functions as Linux

Audit the LFS functions from Linux and add the same for Android if
bionic supports it, according to libc.map from API 23 (Android 6.0).

The standard library is currently limited to API 18, so it may only use
`lseek64`, `pread64`, `pwrite64`, `ftruncate64`, and `readahead`.

Note that `stat64` and `dirent64` are actually identical to the regular
versions, because bionic has always mapped them to the LFS syscalls.
It also sets `O_LARGEFILE` at all times, so `open` matches `open64`.
Still, the explicit LFS names may be useful to match Linux.

Fixes #189.

src/unix/notbsd/android/mod.rs

@@ -8,6 +8,7 @@ pub type time_t = i32;
 pub type suseconds_t = i32;
 pub type wchar_t = u32;
 pub type off_t = i32;
+pub type off64_t = i64;
 pub type ino_t = u32;
 pub type blkcnt_t = u32;
 pub type blksize_t = u32;
@@ -48,6 +49,28 @@ s! {
         pub st_ino: ::c_ulonglong,
     }
 
+    pub struct stat64 {
+        pub st_dev: ::c_ulonglong,
+        __pad0: [::c_uchar; 4],
+        __st_ino: ::ino_t,
+        pub st_mode: ::c_uint,
+        pub st_nlink: ::c_uint,
+        pub st_uid: ::uid_t,
+        pub st_gid: ::gid_t,
+        pub st_rdev: ::c_ulonglong,
+        __pad3: [::c_uchar; 4],
+        pub st_size: ::c_longlong,
+        pub st_blksize: blksize_t,
+        pub st_blocks: ::c_ulonglong,
+        pub st_atime: ::c_ulong,
+        pub st_atime_nsec: ::c_ulong,
+        pub st_mtime: ::c_ulong,
+        pub st_mtime_nsec: ::c_ulong,
+        pub st_ctime: ::c_ulong,
+        pub st_ctime_nsec: ::c_ulong,
+        pub st_ino: ::c_ulonglong,
+    }
+
     pub struct dirent {
         pub d_ino: u64,
         pub d_off: i64,
@@ -56,6 +79,19 @@ s! {
         pub d_name: [::c_char; 256],
     }
 
+    pub struct dirent64 {
+        pub d_ino: u64,
+        pub d_off: i64,
+        pub d_reclen: ::c_ushort,
+        pub d_type: ::c_uchar,
+        pub d_name: [::c_char; 256],
+    }
+
+    pub struct rlimit64 {
+        pub rlim_cur: u64,
+        pub rlim_max: u64,
+    }
+
     pub struct pthread_attr_t {
         pub flags: ::uint32_t,
         pub stack_base: *mut ::c_void,
@@ -588,6 +624,30 @@ extern {
     pub fn timegm64(tm: *const ::tm) -> time64_t;
     pub fn eventfd(init: ::c_uint, flags: ::c_int) -> ::c_int;
     pub fn ptrace(request: ::c_int, ...) -> ::c_long;
+    pub fn fstat64(fildes: ::c_int, buf: *mut stat64) -> ::c_int;
+    pub fn stat64(path: *const c_char, buf: *mut stat64) -> ::c_int;
+    pub fn open64(path: *const c_char, oflag: ::c_int, ...) -> ::c_int;
+    pub fn creat64(path: *const c_char, mode: mode_t) -> ::c_int;
+    pub fn lseek64(fd: ::c_int, offset: off64_t, whence: ::c_int) -> off64_t;
+    pub fn pread64(fd: ::c_int, buf: *mut ::c_void, count: ::size_t,
+                   offset: off64_t) -> ::ssize_t;
+    pub fn pwrite64(fd: ::c_int, buf: *const ::c_void, count: ::size_t,
+                    offset: off64_t) -> ::ssize_t;
+    pub fn mmap64(addr: *mut ::c_void,
+                  len: ::size_t,
+                  prot: ::c_int,
+                  flags: ::c_int,
+                  fd: ::c_int,
+                  offset: off64_t)
+                  -> *mut ::c_void;
+    pub fn lstat64(path: *const c_char, buf: *mut stat64) -> ::c_int;
+    pub fn ftruncate64(fd: ::c_int, length: off64_t) -> ::c_int;
+    pub fn readdir64_r(dirp: *mut ::DIR, entry: *mut ::dirent64,
+                       result: *mut *mut ::dirent64) -> ::c_int;
+    pub fn getrlimit64(resource: ::c_int, rlim: *mut rlimit64) -> ::c_int;
+    pub fn setrlimit64(resource: ::c_int, rlim: *const rlimit64) -> ::c_int;
+    pub fn readahead(fd: ::c_int, offset: ::off64_t,
+                     count: ::size_t) -> ::ssize_t;
 }
 
 cfg_if! {