Extension Installer Catch 22

I'm writing an extension installer. I want to write the installer in PHP. This presents a problem if the extension was previously installed and is automatically being loaded because it can segfault after overwriting the .so module file. Can someone recommend a method to avoid this? I can think of a few: 1) Use the -c argument to php to load a custom minimalistic php.ini file that does load the extension being installed. The downside to this is that I would like to detect within the installer if the extension is already installed and is being loaded automatically. 2) Use -d installer=yes to enable the extension to detect when it is being loaded by the installer and return FALSE to indicate the extension was not loaded. The downside to this is that a warning is printed if the modudule initialization routine fails to load. Any other ideas? Thanks, Mike