Populate tree.

src/lib/linux_os.rs

@@ -0,0 +1,19 @@
+import _str.sbuf;
+import _vec.vbuf;
+
+native mod libc = "libc.so.6" {
+
+  fn open(sbuf s, int flags) -> int;
+  fn read(int fd, vbuf buf, uint count) -> int;
+  fn write(int fd, vbuf buf, uint count) -> int;
+  fn close(int fd) -> int;
+
+  type dir;
+  // readdir is a mess; handle via wrapper function in rustrt.
+  fn opendir(sbuf d) -> dir;
+  fn closedir(dir d) -> int;
+
+  fn getenv(sbuf n) -> sbuf;
+  fn setenv(sbuf n, sbuf v, int overwrite) -> int;
+  fn unsetenv(sbuf n) -> int;
+}