These include stubs are given in the comments within
rapidjson.h and are preported as error by the presubmission
check.

Bug: angleproject:5765
Change-Id: Ic200a860de7337aefcd3bb0f82686d62a1349d89
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2765648Reviewed-by: Cody Northrop <cnorthrop@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Gert Wollny <gert.wollny@collabora.com>