Gentoo's Bugzilla –
Attachment 531878 Details for
Bug 655934app-office/gnucash-3.1 - In file included from .../work/gnucash-3.1/gnucash/import-export/csv-imp/assistant-csv-price-import.cpp:36: /usr/include/gtk-3.0/gtk/gtkfilechooserbutton.h:66:8: error: unnecessary parentheses in declaration of ‘__gtk_reserved1’