brianmario/mysql2 — pull request #524 by lowjoel (2014-07-11 16:13:45+00:00)
Title: Remove including unistd.h when compiling under Visual C++

Visual Studio doesn't have unistd.h, and mysql2 compiles just fine.

I'm experimenting with Visual Studio-compiled Ruby, trying out a few things. This was necessary for it to compile. I've not verified whether it works, but I believe it is mostly harmless for all other platforms (_MSC_VER is defined only by VC)