TYPO3 Core

The system environment check already has a check for required modules and tests for them. #49458 is clearly a bug and should be fixed by checking for existing method name and otherwise throwing an error status.

The normal check for the required modules is just too late in the process. There is already a lot of functionality from these modules used before this check. It isn't practical to check for each function from these modules.

Hmm, what exactly do you mean? You mention the autoloader using additional php modules, but I can not really find any php module specific code in there. As far as I can see, the environment check class is the first class within the installation process that actually tests for things and checks modules. Method calls in there can be sanitized with function_exist pretty easily.
Even if you have a stripped php environment without many modules, the first step should already come up successfully. The only requirement I can see here is a hard requirement for php 5.3, or you will already fail in the entry script on the first '\' during compile time.