Debug use flag in dia disables deprecated features of gtk+. Dia uses features deprecated in gtk+-2.20, for example: http://library.gnome.org/devel/gtk/stable/GtkWidget.html#GTK-WIDGET-VISIBLE:CAPS Note that x11-libs/gtk+-2.20.1-r1 is already in ~arch.
a build.log and emerge --info would still be nice.
Actually gtk+-2.20 is stable ... so info and log or not, please do look into this. (But Jan, please attach the two if you can).
Created attachment 244149 [details] emerge --info
Created attachment 244151 [details] build log
*** Bug 324655 has been marked as a duplicate of this bug. ***
Until the issue is resolved, I suggest masking the debug use flag.
+ 09 Sep 2010; Pacho Ramos <pacho@gentoo.org> dia-0.97.1.ebuild: + Don't use -DGTK_DISABLE_DEPRECATED (bug #333439) and RDEPEND on gtk+:2. +