Two things were needed:
 - The re-enabling of exception and RTTI as it is disabled in Chromium
   and in a different way than in ANGLE standalone
 - Link decpp with dl

BUG=angleproject:1127

Change-Id: I9ac37545762dc13320c7fba418fba82d7961e83e
Reviewed-on: https://chromium-review.googlesource.com/294822Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Corentin Wallez <cwallez@chromium.org>