graphics/gimp was recently broken by 7b1b252daae due to the new location for iso-codes.pc (see bug 291672) A quick search shows other ports that still reference the old location: chinese/fcitx-configtool chinese/fcitx www/gtkhtml4 graphics/gimp3-app editors/pluma irc/hexchat
Commit 4ae07eaae285 miust be reverted, it violates hier(7)
Fixed in ports ad4b417832a449b73823462e883c4071908da2ca. Thanks. (In reply to Dima Panov from comment #1) share/pkgconfig is a valid location for .pc files since 2022. See ports d48fab59daa56e0b3b6ffecef57a69c32ae9c0a7.