+#if defined(USE_XCB)
+# include <X11/Xlib-xcb.h>
+# include <xcb/xcb.h>
+# include <xcb/glx.h>
+#endif
+
+#ifdef USE_XCB
+
+/**
+ * Exchange a protocol request for glXQueryServerString.
+ */
+char *
+__glXQueryServerString(Display * dpy, int opcode, CARD32 screen, CARD32 name)
+{
+ xcb_connection_t *c = XGetXCBConnection(dpy);
+ xcb_glx_query_server_string_reply_t *reply =
+ xcb_glx_query_server_string_reply(c,
+ xcb_glx_query_server_string(c,
+ screen,
+ name),
+ NULL);
+
+ /* The spec doesn't mention this, but the Xorg server replies with
+ * a string already terminated with '\0'. */
+ uint32_t len = xcb_glx_query_server_string_string_length(reply);
+ char *buf = Xmalloc(len);
+ memcpy(buf, xcb_glx_query_server_string_string(reply), len);
+ free(reply);
+
+ return buf;
+}
+
+/**
+ * Exchange a protocol request for glGetString.
+ */
+char *
+__glXGetString(Display * dpy, int opcode, CARD32 contextTag, CARD32 name)
+{
+ xcb_connection_t *c = XGetXCBConnection(dpy);
+ xcb_glx_get_string_reply_t *reply = xcb_glx_get_string_reply(c,
+ xcb_glx_get_string
+ (c,
+ contextTag,
+ name),
+ NULL);
+
+ /* The spec doesn't mention this, but the Xorg server replies with
+ * a string already terminated with '\0'. */
+ uint32_t len = xcb_glx_get_string_string_length(reply);
+ char *buf = Xmalloc(len);
+ memcpy(buf, xcb_glx_get_string_string(reply), len);
+ free(reply);
+
+ return buf;
+}
+
+#else
+