Allows modules to implement hook_requirements_alter()

My use case is the following:

• My host provider disabled phpinfo() on the server, and in the status report page I see a warning message.
• I would like to have a link on status report page that takes to a page provided from my module, which reports information similar to the one reported by the `phpinfo()` page.
• The system module still output its requirement block, which just shows the warning message about the function being disabled.

It could help if Drupal would allow any module to alter the output of `hook_requirements()` provided by other modules; in my case, it would allow me to replace the warning message caused by the call to a disabled function with a link to a more useful page.