std: add a fs::remove_file function.

src/libstd/freebsd_os.rs

@@ -62,6 +62,7 @@ native mod libc {
     fn mkdir(path: str::sbuf, mode: c_int) -> c_int;
     fn rmdir(path: str::sbuf) -> c_int;
     fn chdir(path: str::sbuf) -> c_int;
+    fn unlink(path: str::sbuf) -> c_int;
 
     fn sysctl(name: *c_int, namelen: c_uint,
               oldp: *u8, &oldlenp: size_t,

src/libstd/fs.rs

@@ -449,6 +449,27 @@ fn homedir() -> option<path> {
     }
 }
 
+/*
+Function: remove_file
+
+Deletes an existing file.
+*/
+fn remove_file(p: path) -> bool {
+    ret unlink(p);
+
+    #[cfg(target_os = "win32")]
+    fn unlink(p: path) -> bool {
+        ret str::as_buf(p, {|buf| os::kernel32::DeleteFileA(buf)});
+    }
+
+    #[cfg(target_os = "linux")]
+    #[cfg(target_os = "macos")]
+    #[cfg(target_os = "freebsd")]
+    fn unlink(_p: path) -> bool {
+        ret str::as_buf(_p, {|buf| os::libc::unlink(buf) == 0i32 });
+    }
+}
+
 #[cfg(test)]
 mod tests {
     #[test]

src/libstd/linux_os.rs

@@ -63,6 +63,7 @@ native mod libc {
     fn mkdir(path: str::sbuf, mode: c_int) -> c_int;
     fn rmdir(path: str::sbuf) -> c_int;
     fn chdir(path: str::sbuf) -> c_int;
+    fn unlink(path: str::sbuf) -> c_int;
 }
 
 mod libc_constants {

src/libstd/macos_os.rs

@@ -55,6 +55,7 @@ native mod libc {
     fn mkdir(s: str::sbuf, mode: c_int) -> c_int;
     fn rmdir(s: str::sbuf) -> c_int;
     fn chdir(s: str::sbuf) -> c_int;
+    fn unlink(path: str::sbuf) -> c_int;
 
     // FIXME: Needs varags
     fn fcntl(fd: fd_t, cmd: c_int) -> c_int;

src/libstd/win32_os.rs

@@ -62,6 +62,7 @@ native mod kernel32 {
                         lpSecurityAttributes: LPSECURITY_ATTRIBUTES) -> bool;
     fn RemoveDirectoryA(lpPathName: LPCTSTR) -> bool;
     fn SetCurrentDirectoryA(lpPathName: LPCTSTR) -> bool;
+    fn DeleteFileA(lpFileName: LPCTSTR) -> bool;
 }
 
 // FIXME turn into constants