The proposed solution is in the tracker. If this is an autotools based package, and '--disable-silent-rules' doesn't work, you can try to add MAKEOPTS+=" V=1"
+ 14 Nov 2012; Mike Gilbert <floppym@gentoo.org> libvncserver-0.9.7.ebuild, + libvncserver-0.9.8.2-r2.ebuild, libvncserver-0.9.9.ebuild: + Pass --disable-silent-rules to econf, bug 443128 by ago.