Export a generic dri_bo handle for use by clients

We'll need something like this (either a handle field or a dri_bo_get_handle
function) for kernel mode setting to get at the handles.

libdrm/dri_bufmgr.h

@@ -58,6 +58,10 @@ struct _dri_bo {
    void *virtual;
    /** Buffer manager context associated with this buffer object */
    dri_bufmgr *bufmgr;
+   /**
+    * MM-specific handle for accessing object
+    */
+   int handle;
 };
 
 /**

libdrm/intel/intel_bufmgr_gem.c

@@ -311,6 +311,7 @@ dri_gem_bo_alloc(dri_bufmgr *bufmgr, const char *name,
 
 	ret = ioctl(bufmgr_gem->fd, DRM_IOCTL_I915_GEM_CREATE, &create);
 	bo_gem->gem_handle = create.handle;
+	bo_gem->bo.handle = bo_gem->gem_handle;
 	if (ret != 0) {
 	    free(bo_gem);
 	    return NULL;