Gentoo's Bugzilla –
Attachment 472172 Details for
Bug 618054dev-db/mysql-connector-c-6.1.9-r1 with sys-devel/gcc-7.1.0 - .../work/mysql-connector-c-6.1.9-src/sql-common/client_authentication.cc:86:59: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]