Code base case sensitivity

Hello,

Sorry if this has been mentioned already but haproxy code base contains case colliding entries, namely CONTRIB and contrib/. When checkouting current git HEAD on a case insensitive system (Windows, OSX with default options), you get at best weird behaviours about missing files.

I know this is a linux/unix-based project but given only two entries are affected by this issue, it might be easy to fix and suddenly let people with case-insensitive filesystems operate on the repository like everybody else, and who knows, provide minor documentation fixes.

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Patrick Mézard