auto merge of #6358 : crabtw/rust/mips-segstk, r=brson

I changed ```RED_ZONE_SIZE``` to ```RZ_MAC_32``` because of stack canary failure.
Here is a LLVM patch for MIPS segmented stacks.
http://people.cs.nctu.edu.tw/~jyyou/rust/mips-segstk.patch

Current test results
```
failures:
    rand::tests::test_rng_seeded_custom_seed2
    run::tests::test_forced_destroy_actually_kills
    run::tests::test_unforced_destroy_actually_kills
    time::tests::run_tests
    uv_ll::test::test_uv_ll_struct_size_addrinfo
    uv_ll::test::test_uv_ll_struct_size_uv_timer_t

segfaults:
    rt::io::option::test::test_option_writer_error
    rt::local_services::test::unwind
    rt::sched::test_swap_tasks_then
    stackwalk::test_simple
    stackwalk::test_simple_deep
```

2 files changed, 115 insertions, 2 deletions

diff --git a/src/libcore/libc.rs b/src/libcore/libc.rs
index 6fb4572913d..7ae3f0fd2d4 100644
--- a/src/libcore/libc.rs
+++ b/src/libcore/libc.rs
@@ -268,7 +268,7 @@ pub mod types {
                 pub type ssize_t = i32;
             }
             pub mod posix01 {
-                use libc::types::os::arch::c95::{c_short, c_long, time_t};
+                use libc::types::os::arch::c95::{c_short, c_long, c_ulong, time_t};
                 use libc::types::os::arch::posix88::{dev_t, gid_t, ino_t};
                 use libc::types::os::arch::posix88::{mode_t, off_t};
                 use libc::types::os::arch::posix88::{uid_t};
@@ -276,6 +276,9 @@ pub mod types {
                 pub type nlink_t = u32;
                 pub type blksize_t = i32;
                 pub type blkcnt_t = i32;
+
+                #[cfg(target_arch = "x86")]
+                #[cfg(target_arch = "arm")]
                 pub struct stat {
                     st_dev: dev_t,
                     __pad1: c_short,
@@ -298,6 +301,30 @@ pub mod types {
                     __unused4: c_long,
                     __unused5: c_long,
                 }
+
+                #[cfg(target_arch = "mips")]
+                pub struct stat {
+                    st_dev: c_ulong,
+                    st_pad1: [c_long, ..3],
+                    st_ino: ino_t,
+                    st_mode: mode_t,
+                    st_nlink: nlink_t,
+                    st_uid: uid_t,
+                    st_gid: gid_t,
+                    st_rdev: c_ulong,
+                    st_pad2: [c_long, ..2],
+                    st_size: off_t,
+                    st_pad3: c_long,
+                    st_atime: time_t,
+                    st_atime_nsec: c_long,
+                    st_mtime: time_t,
+                    st_mtime_nsec: c_long,
+                    st_ctime: time_t,
+                    st_ctime_nsec: c_long,
+                    st_blksize: blksize_t,
+                    st_blocks: blkcnt_t,
+                    st_pad5: [c_long, ..14],
+                }
             }
             pub mod posix08 {}
             pub mod bsd44 {}
@@ -963,6 +990,9 @@ pub mod consts {
         }
         pub mod c99 {
         }
+        #[cfg(target_arch = "x86")]
+        #[cfg(target_arch = "x86_64")]
+        #[cfg(target_arch = "arm")]
         pub mod posix88 {
             pub static O_RDONLY : int = 0;
             pub static O_WRONLY : int = 1;
@@ -1007,6 +1037,51 @@ pub mod consts {
             pub static SIGALRM : int = 14;
             pub static SIGTERM : int = 15;
         }
+        #[cfg(target_arch = "mips")]
+        pub mod posix88 {
+            pub static O_RDONLY : int = 0;
+            pub static O_WRONLY : int = 1;
+            pub static O_RDWR : int = 2;
+            pub static O_APPEND : int = 8;
+            pub static O_CREAT : int = 256;
+            pub static O_EXCL : int = 1024;
+            pub static O_TRUNC : int = 512;
+            pub static S_IFIFO : int = 4096;
+            pub static S_IFCHR : int = 8192;
+            pub static S_IFBLK : int = 24576;
+            pub static S_IFDIR : int = 16384;
+            pub static S_IFREG : int = 32768;
+            pub static S_IFMT : int = 61440;
+            pub static S_IEXEC : int = 64;
+            pub static S_IWRITE : int = 128;
+            pub static S_IREAD : int = 256;
+            pub static S_IRWXU : int = 448;
+            pub static S_IXUSR : int = 64;
+            pub static S_IWUSR : int = 128;
+            pub static S_IRUSR : int = 256;
+            pub static F_OK : int = 0;
+            pub static R_OK : int = 4;
+            pub static W_OK : int = 2;
+            pub static X_OK : int = 1;
+            pub static STDIN_FILENO : int = 0;
+            pub static STDOUT_FILENO : int = 1;
+            pub static STDERR_FILENO : int = 2;
+            pub static F_LOCK : int = 1;
+            pub static F_TEST : int = 3;
+            pub static F_TLOCK : int = 2;
+            pub static F_ULOCK : int = 0;
+            pub static SIGHUP : int = 1;
+            pub static SIGINT : int = 2;
+            pub static SIGQUIT : int = 3;
+            pub static SIGILL : int = 4;
+            pub static SIGABRT : int = 6;
+            pub static SIGFPE : int = 8;
+            pub static SIGKILL : int = 9;
+            pub static SIGSEGV : int = 11;
+            pub static SIGPIPE : int = 13;
+            pub static SIGALRM : int = 14;
+            pub static SIGTERM : int = 15;
+        }
         pub mod posix01 {
             pub static SIGTRAP : int = 5;
 
@@ -1026,11 +1101,20 @@ pub mod consts {
         }
         pub mod bsd44 {
         }
+        #[cfg(target_arch = "x86")]
+        #[cfg(target_arch = "x86_64")]
+        #[cfg(target_arch = "arm")]
         pub mod extra {
             pub static O_RSYNC : int = 1052672;
             pub static O_DSYNC : int = 4096;
             pub static O_SYNC : int = 1052672;
         }
+        #[cfg(target_arch = "mips")]
+        pub mod extra {
+            pub static O_RSYNC : int = 16400;
+            pub static O_DSYNC : int = 16;
+            pub static O_SYNC : int = 16400;
+        }
     }
 
     #[cfg(target_os = "freebsd")]
diff --git a/src/libcore/path.rs b/src/libcore/path.rs
index a87fd90f4e2..d3010aff3e8 100644
--- a/src/libcore/path.rs
+++ b/src/libcore/path.rs
@@ -122,7 +122,6 @@ pub trait GenericPath {
 mod stat {
     #[cfg(target_arch = "x86")]
     #[cfg(target_arch = "arm")]
-    #[cfg(target_arch = "mips")]
     pub mod arch {
         use libc;
 
@@ -152,6 +151,36 @@ mod stat {
         }
     }
 
+    #[cfg(target_arch = "mips")]
+    pub mod arch {
+        use libc;
+
+        pub fn default_stat() -> libc::stat {
+            libc::stat {
+                st_dev: 0,
+                st_pad1: [0, ..3],
+                st_ino: 0,
+                st_mode: 0,
+                st_nlink: 0,
+                st_uid: 0,
+                st_gid: 0,
+                st_rdev: 0,
+                st_pad2: [0, ..2],
+                st_size: 0,
+                st_pad3: 0,
+                st_atime: 0,
+                st_atime_nsec: 0,
+                st_mtime: 0,
+                st_mtime_nsec: 0,
+                st_ctime: 0,
+                st_ctime_nsec: 0,
+                st_blksize: 0,
+                st_blocks: 0,
+                st_pad5: [0, ..14],
+            }
+        }
+    }
+
     #[cfg(target_arch = "x86_64")]
     pub mod arch {
         use libc;