If Emulate3Buttons is specified in the config, don't auto-deactivate it.

Default setting is still "on" until middle button is pressed.  If the options
is however explicitly stated in the config file, it takes the value from the
config file, no matter if a middle button is present.

src/emuMB.c

@@ -36,6 +36,12 @@
 
 #include "evdev.h"
 
+enum {
+    MBEMU_DISABLED = 0,
+    MBEMU_ENABLED,
+    MBEMU_AUTO
+};
+
 /*
  * Lets create a simple finite-state machine for 3 button emulation:
  *
@@ -288,9 +294,17 @@ void
 EvdevMBEmuPreInit(InputInfoPtr pInfo)
 {
     EvdevPtr pEvdev = (EvdevPtr)pInfo->private;
+    pEvdev->emulateMB.enabled = MBEMU_AUTO;
+
+    if (xf86FindOption(pInfo->options, "Emulate3Buttons"))
+    {
+        pEvdev->emulateMB.enabled = xf86SetBoolOption(pInfo->options,
+                                                      "Emulate3Buttons",
+                                                      MBEMU_ENABLED);
+        xf86Msg(X_INFO, "%s: Forcing middle mouse button emulation.\n",
+                        pInfo->name);
+    }
 
-    pEvdev->emulateMB.enabled = xf86SetBoolOption(pInfo->options,
-                                                  "Emulate3Buttons", TRUE);
     pEvdev->emulateMB.timeout = xf86SetIntOption(pInfo->options,
                                                  "Emulate3Timeout", 50);
     RegisterBlockAndWakeupHandlers (EvdevMBEmuBlockHandler,
@@ -313,5 +327,6 @@ void
 EvdevMBEmuEnable(InputInfoPtr pInfo, BOOL enable)
 {
     EvdevPtr pEvdev = (EvdevPtr)pInfo->private;
-    pEvdev->emulateMB.enabled = enable;
+    if (pEvdev->emulateMB.enabled == MBEMU_AUTO)
+        pEvdev->emulateMB.enabled = enable;
 }