Rollup merge of #21387 - retep998:hmodule, r=alexcrichton

r? @alexcrichton

src/liblibc/lib.rs

@@ -1541,7 +1541,8 @@ pub mod types {
                 pub type DWORDLONG = c_ulonglong;
 
                 pub type HANDLE = LPVOID;
-                pub type HMODULE = c_uint;
+                pub type HINSTANCE = HANDLE;
+                pub type HMODULE = HINSTANCE;
 
                 pub type LONG = c_long;
                 pub type PLONG = *mut c_long;

src/libstd/sys/windows/os.rs

@@ -281,7 +281,7 @@ pub fn join_paths<T: BytesContainer>(paths: &[T]) -> Result<Vec<u8>, &'static st
 pub fn load_self() -> Option<Vec<u8>> {
     unsafe {
         fill_utf16_buf_and_decode(|buf, sz| {
-            libc::GetModuleFileNameW(0u as libc::DWORD, buf, sz)
+            libc::GetModuleFileNameW(ptr::null_mut(), buf, sz)
         }).map(|s| s.to_string().into_bytes())
     }
 }