xkb: delete default rules when devices are closed.

We only have one set of default rules options in xkb. When the second keyboard
is brought up with Xkb options specified, these new options overwrite the old.
In future server generations, the rules used for the VCK are a mixture of the
default ones and ones previously specified for other keyboards. Simply
resetting the xkb default rules to NULL avoids this issue.

Reproducable by setting XkbLayout "de" and XkbVariant "nodeadkeys". In the
second server generation, the VCK has "us(nodeadkeys)". This again produces a
SIGABRT when the first key is hit.

I could not figure out why the SIGABRT happens. This patch is avoiding the
issue rather than fixing it.

dix/devices.c

@@ -847,6 +847,9 @@ CloseDownDevices(void)
     inputInfo.off_devices = NULL;
     inputInfo.keyboard = NULL;
     inputInfo.pointer = NULL;
+#ifdef XKB
+    XkbDeleteRulesDflts();
+#endif
 }
 
 /**

include/xkbsrv.h

@@ -899,6 +899,10 @@ extern	void	XkbSetRulesDflts(
 	char *			/* options */
 );
 
+extern	void	XkbDeleteRulesDflts(
+	void
+);
+
 extern	void	XkbInitDevice(
 	DeviceIntPtr 	/* pXDev */
 );

xkb/xkbInit.c

@@ -279,6 +279,21 @@ XkbSetRulesDflts(char *rulesFile,char *model,char *layout,
     return;
 }
 
+void
+XkbDeleteRulesDflts()
+{
+    _XkbFree(XkbRulesFile);
+    XkbRulesFile = NULL;
+    _XkbFree(XkbModelDflt);
+    XkbModelDflt = NULL;
+    _XkbFree(XkbLayoutDflt);
+    XkbLayoutDflt = NULL;
+    _XkbFree(XkbVariantDflt);
+    XkbVariantDflt = NULL;
+    _XkbFree(XkbOptionsDflt);
+    XkbOptionsDflt = NULL;
+}
+
 /***====================================================================***/
 
 #include "xkbDflts.h"