GCC: fix deprecated copy warnings

As of C++11, implicit generation of the copy assignment operator
is declared as deprecated. This creates a lot of warnings with
GCC.

Change-Id: I9ed294924bba697e85df334d93b534713fb61c4a
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/12360
Reviewed-by: Brett Wilson <[email protected]>
Commit-Queue: Brett Wilson <[email protected]>
diff --git a/AUTHORS b/AUTHORS
index 2e9eb5a..755bfd4 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -40,6 +40,7 @@
 Raphael Kubo da Costa <[email protected]>
 Riku Voipio <[email protected]>
 Saikrishna Arcot <[email protected]>
+Stephan Hartmann <[email protected]>
 Tim Niederhausen <[email protected]>
 Tomas Popela <[email protected]>
 Tripta Gupta <[email protected]>