mesa: Add gl_shared_state::ShareGroupReset and gl_context::ShareGroupReset

These will be used to determine whether to signal a GPU reset after
another context in the share group has observed a reset.

v2: Change ShareGroupReset from GLboolean to bool.  Suggested by Brian.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

src/mesa/main/context.c

@@ -808,6 +808,7 @@ init_attrib_groups(struct gl_context *ctx)
    ctx->NewState = _NEW_ALL;
    ctx->NewDriverState = ~0;
    ctx->ErrorValue = GL_NO_ERROR;
+   ctx->ShareGroupReset = false;
    ctx->varying_vp_inputs = VERT_BIT_ALL;
 
    return GL_TRUE;