Work around linkage bug cross-compiling from x86_64-apple-darwin to i686-apple-darwin

The correct opendir/readdir to use appear to be the 64-bit versions called
opendir$INODE64, etc. but for some reason I can't get them to link properly
on i686. Putting them in librustrt and making gcc figure it out works.
This mystery will have to wait for another day.

Author: brson

src/libcore/libc.rs

@@ -1385,48 +1385,30 @@ pub mod funcs {
             use libc::types::common::posix88::{DIR, dirent_t};
             use libc::types::os::arch::c95::{c_char, c_int, c_long};
 
-            pub extern {
-                // default bindings for opendir and readdir in
-                // non-macos unix
-                #[cfg(target_os = "linux")]
-                #[cfg(target_os = "android")]
-                #[cfg(target_os = "freebsd")]
-                unsafe fn opendir(dirname: *c_char) -> *DIR;
-                #[cfg(target_os = "linux")]
-                #[cfg(target_os = "android")]
-                #[cfg(target_os = "freebsd")]
-                unsafe fn readdir(dirp: *DIR) -> *dirent_t;
+            // NOTE: On OS X opendir and readdir have two versions,
+            // one for 32-bit kernelspace and one for 64.
+            // We should be linking to the 64-bit ones, called
+            // opendir$INODE64, etc. but for some reason rustc
+            // doesn't link it correctly on i686, so we're going
+            // through a C function that mysteriously does work.
+            pub unsafe fn opendir(dirname: *c_char) -> *DIR {
+                rust_opendir(dirname)
+            }
+            pub unsafe fn readdir(dirp: *DIR) -> *dirent_t {
+                rust_readdir(dirp)
+            }
+
+            extern {
+                unsafe fn rust_opendir(dirname: *c_char) -> *DIR;
+                unsafe fn rust_readdir(dirp: *DIR) -> *dirent_t;
+            }
 
+            pub extern {
                 unsafe fn closedir(dirp: *DIR) -> c_int;
                 unsafe fn rewinddir(dirp: *DIR);
                 unsafe fn seekdir(dirp: *DIR, loc: c_long);
                 unsafe fn telldir(dirp: *DIR) -> c_long;
             }
-
-            #[cfg(target_word_size = "64")]
-            pub extern {
-                // on OSX (particularly when running with a
-                // 64bit kernel), we have an issue where there
-                // are separate bindings for opendir and readdir,
-                // which we have to explicitly link, as below.
-                #[cfg(target_os = "macos")]
-                #[link_name = "opendir$INODE64"]
-                unsafe fn opendir(dirname: *c_char) -> *DIR;
-                #[cfg(target_os = "macos")]
-                #[link_name = "readdir$INODE64"]
-                unsafe fn readdir(dirp: *DIR) -> *dirent_t;
-            }
-            #[cfg(target_word_size = "32")]
-            pub extern {
-                // on OSX (particularly when running with a
-                // 64bit kernel), we have an issue where there
-                // are separate bindings for opendir and readdir,
-                // which we have to explicitly link, as below.
-                #[cfg(target_os = "macos")]
-                unsafe fn opendir(dirname: *c_char) -> *DIR;
-                #[cfg(target_os = "macos")]
-                unsafe fn readdir(dirp: *DIR) -> *dirent_t;
-            }
         }
 
         #[nolink]

src/libuv

@@ -818,6 +818,33 @@ rust_dec_kernel_live_count() {
     task->kernel->dec_live_count();
 }
 
+#ifndef _WIN32
+#include <sys/types.h>
+#include <dirent.h>
+
+extern "C" DIR*
+rust_opendir(char *dirname) {
+    return opendir(dirname);
+}
+
+extern "C" dirent*
+rust_readdir(DIR *dirp) {
+    return readdir(dirp);
+}
+
+#else
+
+extern "C" void
+rust_opendir() {
+}
+
+extern "C" void
+rust_readdir() {
+}
+
+#endif
+
+
 //
 // Local Variables:
 // mode: C++

src/rt/rust_builtin.cpp

@@ -194,3 +194,5 @@ rust_dec_kernel_live_count
 rust_get_exchange_count_ptr
 rust_get_sched_tls_key
 swap_registers
+rust_readdir
+rust_opendir