i installed php7-dev version http://php-osx.liip.ch/ , install process happens without problem.
unfortunately when try install mongo (or matter) pecl extension can't message : not open input file: /usr/local/php5/lib/php/peclcmd.php
when install 5.6.8 same source have no problem.
i've compared both directories , indeed missing
ls -lsa /usr/local/php5-7.0.0-dev-20150417-194402/lib/php/ total 4 0 drwxr-xr-x 4 root wheel 136 apr 22 21:18 . 0 drwxr-xr-x 197 root wheel 6698 apr 22 21:18 .. 4 lrwxr-xr-x 1 root wheel 25 apr 22 21:18 build -> /usr/local/php5/lib/build 0 drwxr-xr-x 3 root wheel 102 apr 22 21:18 extensions vs
ls -lsa /usr/local/php5-5.6.8-20150417-141945/lib/php/peclcmd.php 4 -rw-r--r-- 1 root wheel 1022 apr 17 08:19 /usr/local/php5-5.6.8-20150417-141945/lib/php/peclcmd.php
the pecl command dependant on pear, since pear not coming php7, moment must install extensions manually.
there talk of new package manager extensions, though no concrete plans aware of.
when changes, , might, update answer.
