libphp5.so not being created after compiling and prefix directory not created
As per the php INSTALL file (which I can't fault you for not reading in its entirety... I spent an hour on google before sitting down and reading the whole thing), you need to make sure apache is installed with
./configure --enable-sobefore configuring and making php with
./configure --with-apxs2=/usr/local/apache2/bin/apxs