php-json is branched but not built for EL5. The php-json package from FC6 rebuilds fine : http://archives.fedoraproject.org/pub/archive/fedora/linux/extras/6/SRPMS/php-json-1.2.1-5.fc6.src.rpm Would it be possible to build it ?
Arg.. I always think it's available. I should have not look in CVS... :( I will build it. +
In fact php-pecl-json is available in EPEL-5.