Ignore gui_mch_update()

By making gui_mch_update() a no-op the frame-rate is dramatically
increased in certain situations.  The downside is that it is no longer
possible to interrupt Vim with Ctrl-C when it is busy processing.

src/MacVim/MMBackend.m

@@ -466,10 +466,6 @@ static NSString *MMSymlinkWarningString =
 
 - (void)update
 {
-    // Tend to the run loop, returning immediately if there are no events
-    // waiting.
-    [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode
-                             beforeDate:[NSDate distantPast]];
 }
 
 - (void)flushQueue:(BOOL)force

src/MacVim/gui_macvim.m

@@ -20,10 +20,6 @@
 
 
 
-// This constant controls how often [MMBackend update] may get called (see
-// gui_mch_update()).
-static NSTimeInterval MMUpdateTimeoutInterval = 0.1f;
-
 // NOTE: The default font is bundled with the application.
 static NSString *MMDefaultFontName = @"DejaVu Sans Mono";
 static float MMDefaultFontSize = 12.0f;
@@ -185,39 +181,13 @@ gui_mch_open(void)
  * nothing in the X event queue (& no timers pending), then we return
  * immediately.
  */
-#define MM_LOG_UPDATE_STATS 0
     void
 gui_mch_update(void)
 {
-    // NOTE: This function can get called A LOT (~1 call/ms) and unfortunately
-    // checking the run loop takes a long time, resulting in noticable slow
-    // downs if it is done every time this function is called.  Therefore we
-    // make sure that it is not done too often.
-    static NSDate *lastUpdateDate = nil;
-#if MM_LOG_UPDATE_STATS
-    static int skipCount = 0;
-#endif
-
-    if (lastUpdateDate && -[lastUpdateDate timeIntervalSinceNow] <
-            MMUpdateTimeoutInterval) {
-#if MM_LOG_UPDATE_STATS
-        ++skipCount;
-#endif
-        return;
-    }
-
-#if MM_LOG_UPDATE_STATS
-    NSTimeInterval dt = -[lastUpdateDate timeIntervalSinceNow];
-    NSLog(@"Updating (last update %.2f seconds ago, skipped %d updates, "
-            "approx %.1f calls per second)",
-            dt, skipCount, dt > 0 ? skipCount/dt : 0);
-    skipCount = 0;
-#endif
-
-    [[MMBackend sharedInstance] update];
-
-    [lastUpdateDate release];
-    lastUpdateDate = [[NSDate date] retain];
+    // This function is called extremely often.  By doing nothing here the
+    // frame-rate is increased dramatically in certain situations.  However,
+    // the downside is that it is often not possible to interrupt Vim with
+    // Ctrl-C when it is busy processing.
 }