This name has been changed in apache-2.4. The old one will still work, but we should find/replace it in 00_mpm.conf with "MaxConnectionsPerChild". Quoth the upgrading.html: MaxRequestsPerChild has been renamed to MaxConnectionsPerChild, describes more accurately what it does. The old name is still supported.
Thanks for the report. http://git.overlays.gentoo.org/gitweb/?p=proj/apache.git;a=commitdiff;h=021b4ea0c352c3ce95a9461e0f9ed08ef2019c90 This will be in the next gentoo-apache tarball rollout. Please keep this bug open until a fixed apache is in portage.
Fixed in apache-2.4.10-r1