python3 build error

[jfburkhart]

I can build/install no problem in py27 env, but in py3 I get:

$python setup.py build_ext --inplace
Compiling gpd_lite_toolbox/cycartogram.pyx because it changed.
[1/1] Cythonizing gpd_lite_toolbox/cycartogram.pyx
running build_ext
building 'gpd_lite_toolbox.cycartogram' extension
gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -I. -I/opt/anaconda3/envs/py3/include/python3.6m -c gpd_lite_toolbox/cycartogram.c -o build/temp.linux-x86_64-3.6/gpd_lite_toolbox/cycartogram.o
In file included from /opt/anaconda3/envs/py3/include/python3.6m/Python.h:30:0,
                 from gpd_lite_toolbox/cycartogram.c:20:
/usr/include/string.h:544:5: error: unknown type name '__locale_t'
     __locale_t __loc)
     ^
/usr/include/string.h:548:18: error: unknown type name '__locale_t'
      size_t __n, __locale_t __loc)
                  ^
error: command 'gcc' failed with exit status 1