This update for gn, re2 fixes the following issues:

Changes in re2:

Update to 2021-11-01:

* Update Unicode data to 14.0.0
* Address a `-Wshadow' warning

Update to 2021-09-01:

* Permit Unicode characters beyond ASCII in capture names

update to 2021-08-01:

* case-insensitive prefix acceleration

update to 2021-06-01:

* Fix (|a)* matching more text than (|a)+
* build system tweaks and developer visible fixes

Changes in gn:

Update to version 0.20210811:

* C++ modernization improvements.
* Minor style updates.
* Enable GN to build & run on z/OS
* Fix a typo in the doc of "generated_file"
* Update doc/help to say --ninja-executable works for VS Flags
* [rust] Fix and test dylib support
* Add 'rustenv' to 'gn desc' output
* [rust] Clean up logic in PullDependentTargetLibsFrom
* Link Rust binaries against transitive public_deps
* Fix linking dynamic libraries in Rust binaries