feature #1552 Warn when running with xdebug extension (SpacePossum)
feature #1552 Warn when running with xdebug extension (SpacePossum)

This PR was merged into the 1.11 branch.

Discussion
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Warn when running with xdebug extension

Cant recall why I never finished this ^-^
Anyway following composer who warns it users about the impact of xdebug this will warn users in a similar way.
This time the warning is written to stderr (https://github.com/FriendsOfPHP/PHP-CS-Fixer/pull/1245#discussion_r31876821).

Commits
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2667d61 Warn when running xdebug.

Slamdunk/PHP-CS-Fixer,felixgomez/PHP-CS-Fixer,SpacePossum/PHP-CS-Fixer,lmanzke/PHP-CS-Fixer,Soullivaneuh/PHP-CS-Fixer,kubawerlos/PHP-CS-Fixer,kubawerlos/PHP-CS-Fixer,gharlan/PHP-CS-Fixer,felixgomez/PHP-CS-Fixer,GrahamCampbell/PHP-CS-Fixer,FriendsOfPHP/PHP-CS-Fixer,lucasmichot/PHP-CS-Fixer,FriendsOfPHP/PHP-CS-Fixer,gharlan/PHP-CS-Fixer,Slamdunk/PHP-CS-Fixer,keradus/PHP-CS-Fixer,keradus/PHP-CS-Fixer,lmanzke/PHP-CS-Fixer,Soullivaneuh/PHP-CS-Fixer,lucasmichot/PHP-CS-Fixer,SpacePossum/PHP-CS-Fixer,GrahamCampbell/PHP-CS-Fixer