Enable build for 32-bit version of Python

The '-A' platform name is required on Windows.
This option was added in CMake v3.1.

.appveyor.yml

@@ -1,17 +1,20 @@
 version: '{build}'
 os: Visual Studio 2015
 environment:
- PATH: C:\Miniconda35-x64\Scripts\;%PATH%
  PB_WERROR: 1
  PYPI_USER:
  secure: VNmO0xqOUrgWa0uT/HO/mg==
  PYPI_PASS:
  secure: gqNQRQIXkXmSul5JkOKj4owHUprr3Q4gJ6U6Mtlgm4M=
+ matrix:
+ - PATH: C:\Miniconda35-x64\Scripts\;%PATH%
+ - PATH: C:\Miniconda35\Scripts\;%PATH%
 install:
  - cmd: git submodule update -q --init --recursive
  - cmd: conda update -y -q conda
- - cmd: conda create -y -q -n pb35 python=3.5 numpy scipy matplotlib wheel
+ - cmd: conda create -y -q -n pb35 python=3.5 numpy scipy matplotlib
  - cmd: activate pb35
+ - cmd: pip install -U -q wheel
  - cmd: pip install -q twine
 build_script:
  - cmd: python setup.py build_ext

setup.py

@@ -10,11 +10,7 @@
 
 
 if sys.version_info[:2] < (3, 4):
- print("Python >= 3.4 is required. It must also be 64-bit.")
- sys.exit(-1)
-
-if sys.maxsize <= 2**32:
- print("A 64-bit version of Python >= 3.4 is required")
+ print("Python >= 3.4 is required.")
  sys.exit(-1)
 
 
@@ -27,7 +23,7 @@ def __init__(self, name, sourcedir=''):
 class CMakeBuild(build_ext):
  def run(self):
  if shutil.which('cmake') is None:
- print("CMake 3.0 or newer is required to build pybinding")
+ print("CMake 3.1 or newer is required to build pybinding")
  sys.exit(-1)
 
  for ext in self.extensions:
@@ -42,8 +38,9 @@ def run(self):
  build_args = ['--config', 'Release']
 
  if platform.system() == "Windows":
- cmake_args += ['-DCMAKE_LIBRARY_OUTPUT_DIRECTORY_RELEASE=' + extfulldir,
- '-G', 'Visual Studio 14 2015 Win64']
+ cmake_args += ['-DCMAKE_LIBRARY_OUTPUT_DIRECTORY_RELEASE=' + extfulldir]
+ if sys.maxsize > 2**32:
+ cmake_args += ['-A', 'x64']
  build_args += ['--', '/m']
  else:
  build_args += ['--', '-j2']