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/server/debugger.c b/server/debugger.c
index 7f84410..202f0dd 100644
--- a/server/debugger.c
+++ b/server/debugger.c
@@ -92,11 +92,10 @@
 {
     struct process *debugger = event->debugger->process;
     struct thread *thread = event->sender;
-    int handle;
-    
+    handle_t handle;
+
     /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
-    if ((handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE )) == -1)
-        return 0;
+    if (!(handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE ))) return 0;
     event->data.info.create_thread.handle = handle;
     event->data.info.create_thread.teb    = thread->teb;
     event->data.info.create_thread.start  = arg;
@@ -108,25 +107,24 @@
     struct process *debugger = event->debugger->process;
     struct thread *thread = event->sender;
     struct process *process = thread->process;
-    int handle;
+    handle_t handle;
 
     /* documented: PROCESS_VM_READ | PROCESS_VM_WRITE */
-    if ((handle = alloc_handle( debugger, process, PROCESS_ALL_ACCESS, FALSE )) == -1)
-        return 0;
+    if (!(handle = alloc_handle( debugger, process, PROCESS_ALL_ACCESS, FALSE ))) return 0;
     event->data.info.create_process.process = handle;
 
     /* documented: THREAD_GET_CONTEXT | THREAD_SET_CONTEXT | THREAD_SUSPEND_RESUME */
-    if ((handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE )) == -1)
+    if (!(handle = alloc_handle( debugger, thread, THREAD_ALL_ACCESS, FALSE )))
     {
         close_handle( debugger, event->data.info.create_process.process, NULL );
         return 0;
     }
     event->data.info.create_process.thread = handle;
 
-    handle = -1;
+    handle = 0;
     if (process->exe.file &&
         /* the doc says write access too, but this doesn't seem a good idea */
-        ((handle = alloc_handle( debugger, process->exe.file, GENERIC_READ, FALSE )) == -1))
+        !(handle = alloc_handle( debugger, process->exe.file, GENERIC_READ, FALSE )))
     {
         close_handle( debugger, event->data.info.create_process.process, NULL );
         close_handle( debugger, event->data.info.create_process.thread, NULL );
@@ -161,9 +159,9 @@
 {
     struct process *debugger = event->debugger->process;
     struct process_dll *dll = arg;
-    int handle = -1;
+    handle_t handle = 0;
 
-    if (dll->file && (handle = alloc_handle( debugger, dll->file, GENERIC_READ, FALSE )) == -1)
+    if (dll->file && !(handle = alloc_handle( debugger, dll->file, GENERIC_READ, FALSE )))
         return 0;
     event->data.info.load_dll.handle     = handle;
     event->data.info.load_dll.base       = dll->base;
@@ -319,13 +317,13 @@
             close_handle( debugger, event->data.info.create_thread.handle, NULL );
             break;
         case CREATE_PROCESS_DEBUG_EVENT:
-            if (event->data.info.create_process.file != -1)
+            if (event->data.info.create_process.file)
                 close_handle( debugger, event->data.info.create_process.file, NULL );
             close_handle( debugger, event->data.info.create_process.thread, NULL );
             close_handle( debugger, event->data.info.create_process.process, NULL );
             break;
         case LOAD_DLL_DEBUG_EVENT:
-            if (event->data.info.load_dll.handle != -1)
+            if (event->data.info.load_dll.handle)
                 close_handle( debugger, event->data.info.load_dll.handle, NULL );
             break;
         }