Add -Wno-error=narrowing when the architecture has base GCC (and thus
uses new GCC from ports) to prevent the following:

DoublePinyinTable.h:86:1: error: narrowing conversion of '-1' from 'int' to 'char' inside { } [-Wnarrowing]

While here, pet portlint.

PR: 235105
Submitted by: Piotr Kubaj
Approved by: portmgr (tier-2 blanket)