When building syslog-ng-3.1.4 on an old box with dev-libs/libpcre-6.6, I get: [...] checking for PCRE... configure: error: Cannot find pcre version >= 7.3. [...] * ERROR: app-admin/syslog-ng-3.1.4 failed: * econf failed Changing: - pcre? ( dev-libs/libpcre ) to: + pcre? ( >=dev-libs/libpcre-7.3 ) allows the build to complete successfully.
libpcre-6 isn't in the tree anymore. If you only update part of your portage tree you get to keep both pieces when things break.
Sorry, I don't follow. My portage tree is up to date. My pcre wasn't. Simply adding the minimum version to the ebuild triggered the up-to-date pcre to build.
You have packages installed which are long gone from the portage tree. Such packages are unsupportable. To avoid this, use the --update --deep options for emerge.
Marking as invalid per comment 1