Using basically the same setup that works on C6, I have a C7 site.
in PHP.INI, it says “error_log = /tmp/php_errors.log”
PHP errors do not go there (or anywhere).
1. Apache has write perms to /tmp
2. I have restarted httpd since changing php.ini
3. The base php.ini is from the development version in /usr/share
4. Selinux is disabled.