Without the change the build fails against `gcc-13` on `master` as
https://hydra.nixos.org/build/249001657:
In file included from /build/source/shared/qcommon/safe/gsl.h:4,
from /build/source/shared/qcommon/safe/sscanf.h:12,
from /build/source/shared/qcommon/safe/string.h:3,
from /build/source/shared/qcommon/safe/string.cpp:1:
/build/source/lib/gsl-lite/include/gsl/gsl-lite.h:479:18: error: 'reverse_iterator' in namespace 'gsl::std' does not name a template type
479 | typedef std::reverse_iterator< iterator > reverse_iterator;
| ^~~~~~~~~~~~~~~~
0597bbf7d7