Roll buildtools/third_party/libc++abi/trunk/ 4a9d0560b..66967963e (15 commits)

https://chromium.googlesource.com/external/github.com/llvm/llvm-project/libcxxabi.git/+log/4a9d0560b481..66967963e998

Created with:
  roll-dep buildtools/third_party/libc++abi/trunk

Change-Id: Id6530120dab3f057cd75a61eff55236c55174680
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/106970
Reviewed-by: Nigi <nigi@chromium.org>
Commit-Queue: Alan Screen <awscreen@chromium.org>
diff --git a/DEPS b/DEPS
index 42044b3..7e1b267 100644
--- a/DEPS
+++ b/DEPS
@@ -108,7 +108,7 @@
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling libc++abi
   # and whatever else without interference from each other.
-  'libcxxabi_revision': '4a9d0560b481a96821bec591325b50a5063f4a32',
+  'libcxxabi_revision': '66967963e99819e766ccd9037feceb05fbd9b88b',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling libpng
   # and whatever else without interference from each other.