undefined symbol: apr_atomic_xchgptr

When compiling SVN server, and you get this error

undefined symbol: apr_atomic_xchgptr

for my cases, it's due to the SVN library pointing the /usr/lib64 rather than apache's apr, hence you need to recompile your SVN server by pointing your library to where your apache APR located

To find the installed path for a package in Linux

Try this:
rpm -ql packagename

To find a file anywhere on your system:
locate filename
find / -name filename

Fixing a php.ini configuration file location problem

to request the server to change the location where it should read the php.ini from?

Just add an entry in httpd.conf (/etc/httpd/conf/httpd.conf) as following:

PHPIniDir  "/etc"

* make sure your php.ini is under /etc/php.ini

WHEN installing apache 2.2: No recognized SSL/TLS toolkit detected

While running Apache configure, if you get this error:

No recognized SSL/TLS toolkit detected

…do this:

yum install -y openssl-devel # Required for Apache configure