Drop winapi/advapi32 deps

They take a *long* time to compile on Windows and aren't necessarily worth it.

Cargo.toml

@@ -13,18 +13,5 @@ code.
 """
 keywords = ["build-dependencies"]
 
-[target.i686-pc-windows-msvc.dependencies]
-winapi = "0.2.1"
-advapi32-sys = "0.1.2"
-[target.x86_64-pc-windows-msvc.dependencies]
-winapi = "0.2.1"
-advapi32-sys = "0.1.2"
-[target.i686-pc-windows-gnu.dependencies]
-winapi = "0.2.1"
-advapi32-sys = "0.1.2"
-[target.x86_64-pc-windows-gnu.dependencies]
-winapi = "0.2.1"
-advapi32-sys = "0.1.2"
-
 [dev-dependencies]
 tempdir = "0.3"

src/registry.rs

@@ -8,18 +8,56 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-extern crate winapi;
-extern crate advapi32;
-
-use std::io;
 use std::ffi::{OsString, OsStr};
-use std::os::windows::prelude::*;
+use std::io;
 use std::ops::RangeFrom;
-use self::winapi::*;
+use std::os::raw;
-use self::advapi32::*;
+use std::os::windows::prelude::*;
 
 pub struct RegistryKey(Repr);
 
+type HKEY = *mut u8;
+type DWORD = u32;
+type LPDWORD = *mut DWORD;
+type LPCWSTR = *const u16;
+type LPWSTR = *mut u16;
+type LONG = raw::c_long;
+type PHKEY = *mut HKEY;
+type PFILETIME = *mut u8;
+type LPBYTE = *mut u8;
+type REGSAM = u32;
+
+const ERROR_SUCCESS: DWORD = 0;
+const ERROR_NO_MORE_ITEMS: DWORD = 259;
+const HKEY_LOCAL_MACHINE: HKEY = 0x80000002 as HKEY;
+const REG_SZ: DWORD = 1;
+const KEY_READ: DWORD = 0x20019;
+const KEY_WOW64_32KEY: DWORD = 0x200;
+
+#[link(name = "advapi32")]
+extern "system" {
+    fn RegOpenKeyExW(key: HKEY,
+                     lpSubKey: LPCWSTR,
+                     ulOptions: DWORD,
+                     samDesired: REGSAM,
+                     phkResult: PHKEY) -> LONG;
+    fn RegEnumKeyExW(key: HKEY,
+                     dwIndex: DWORD,
+                     lpName: LPWSTR,
+                     lpcName: LPDWORD,
+                     lpReserved: LPDWORD,
+                     lpClass: LPWSTR,
+                     lpcClass: LPDWORD,
+                     lpftLastWriteTime: PFILETIME) -> LONG;
+    fn RegQueryValueExW(hKey: HKEY,
+                        lpValueName: LPCWSTR,
+                        lpReserved: LPDWORD,
+                        lpType: LPDWORD,
+                        lpData: LPBYTE,
+                        lpcbData: LPDWORD) -> LONG;
+    fn RegCloseKey(hKey: HKEY) -> LONG;
+}
+
 struct OwnedKey(HKEY);
 
 enum Repr {