Currently pecl-mongo-1.3.0 is unstable, but now the PECL folks have marked 1.3.2 as stable on December 18 2012 - http://pecl.php.net/package/mongo/1.3.2 There are some bugs in our current stable (1.2.9) that have been fixed in newer versions. These bugs cause a Segfault, so are pretty serious. - https://jira.mongodb.org/browse/PHP-344 so simply pecl-mongo-1.3.0.ebuild to pecl-mongo-1.3.2.ebuild and all seems well here - PHP 5.4.8
Created attachment 334804 [details] pecl-mongo-1.3.2.ebuild bumped EAPI and removed unnecessary dep vars. Builds fine with both php 5.3 and 5.4.
Higher version already in portage. Thanks.