[Bug c++/90809] -finstrument-functions-exclude-function-list mishandles comma escaping

[oliverbrowne627 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90809

--- Comment #2 from Oliver Browne <oliverbrowne627 at gmail dot com> ---
Submitted patch:
https://gcc.gnu.org/ml/gcc-patches/2019-06/msg00722.html

Fixes above issue with bugcase provided