How to force pip to use GCC on OSX?

A bit of an irritating problem with pip on OSX. A python program I am trying to install requires GCC.

The suggested invocation is:

env CC=/usr/local/bin/gcc-6 pip install angr 

However this results in an error suggested OSX decided to run CLANG instead:

clang: error: unknown argument: '-malign-double'

This makes sense since:

$ env CC
clang: error: no input files

Despite the fact that:

$env 
...
cc=/usr/local/bin/gcc-6
CC=/usr/local/bin/gcc-6

Of course I tried:

$CC-/usr/local/bin/gcc-6 
env $CC pip install angr 

but of course:

$ env $CC pip install angr
gcc-6: error: pip: No such file or directory
gcc-6: error: install: No such file or directory
gcc-6: error: angr: No such file or directory
gcc-6: fatal error: no input files

and despite what env tells me just running

$ pip install angr 

results in more

clang: error: unknown argument: '-malign-double'

So what am I missing here? Does OSX hate GCC that bad or is there some basic shell fu I am missing out on here?