Install issue on OS X 10.11.2

[arnikz]

Hi,
During the installation process I encountered the following issue:

    libev/ev.c:1664:22: note: expanded from macro 'array_needsize'
          int ecb_unused ocur_ = (cur);                                     \
                         ^
    14 warnings and 1 error generated.
    error: command 'cc' failed with exit status 1

    ----------------------------------------
  Rolling back uninstall of gevent

So, I thought to share my current solution:)

export CFLAGS='-std=c99
pip install -r requirements

[RinkeHoekstra]

Hi @arnikz thanks for sharing this!
I've had no problems myself, but I remember having to fiddle with some funky cc stuff in the past.

Addendum: the CFLAGS line needs a closing quotation mark:

export CFLAGS='-std=c99'
pip install -r requirements