Initialize Xlib threading support to see what it breaks...

diff --git a/dlls/x11drv/x11drv_main.c b/dlls/x11drv/x11drv_main.c
index 3829847..43ce876 100644
--- a/dlls/x11drv/x11drv_main.c
+++ b/dlls/x11drv/x11drv_main.c
@@ -340,6 +340,8 @@
 
     /* Open display */
 
+    if (!XInitThreads()) ERR( "XInitThreads failed, trouble ahead\n" );
+
     if (!(display = XOpenDisplay( NULL )))
     {
         MESSAGE( "x11drv: Can't open display: %s\n", XDisplayName(NULL) );