If you encounter this error while installing the latest version of kopete:

Linking CXX shared module ../../../lib/kopete_wp.so
[ 51%] Built target kopete_wp                                                                                                                                                                                                                                                  
make: *** [all] Error 2
 * ERROR: kde-base/kopete-4.7.4 failed (compile phase):
 *   emake failed
 * 
 * If you need support, post the output of 'emerge --info =kde-base/kopete-4.7.4',
 * the complete build log and the output of 'emerge -pqv =kde-base/kopete-4.7.4'.
 * The complete build log is located at '/var/tmp/portage/kde-base/kopete-4.7.4/temp/build.log'.
 * The ebuild environment file is located at '/var/tmp/portage/kde-base/kopete-4.7.4/temp/environment'.
 * S: '/var/tmp/portage/kde-base/kopete-4.7.4/work/kopete-4.7.4'

disable the winpopup USE flag. You will lose the ability to send windows network notifications, but chances are you don't use this feature anyway.