Added handle_t type to server interface so that we can make handles
pointers later on.
Always use 0 to signal invalid handle in server requests.

diff --git a/loader/pe_image.c b/loader/pe_image.c
index 74ab2f8..f68f2b7 100644
--- a/loader/pe_image.c
+++ b/loader/pe_image.c
@@ -533,7 +533,7 @@
  * Note: Assumes that the process critical section is held
  */
 WINE_MODREF *PE_CreateModule( HMODULE hModule, LPCSTR filename, DWORD flags,
-                              HFILE hFile, BOOL builtin )
+                              HANDLE hFile, BOOL builtin )
 {
     DWORD load_addr = (DWORD)hModule;  /* for RVA */
     IMAGE_NT_HEADERS *nt = PE_HEADER(hModule);