Based on an environ flag, load the ASIO PortAudio binary

Author: arkrow

setup.py

@@ -23,13 +23,17 @@
     libname = 'libportaudio.dylib'
 elif system == 'Windows':
     libname = 'libportaudio' + architecture0 + '.dll'
+    libname_asio = 'libportaudio' + architecture0 + '-asio.dll'
 else:
     libname = None
 
 if libname and os.path.isdir('_sounddevice_data/portaudio-binaries'):
     packages = ['_sounddevice_data']
     package_data = {'_sounddevice_data': ['portaudio-binaries/' + libname,
                                           'portaudio-binaries/README.md']}
+    if system == 'Windows':
+        package_data['_sounddevice_data'].append(
+            'portaudio-binaries/' + libname_asio)
     zip_safe = False
 else:
     packages = None

sounddevice.py

@@ -74,6 +74,10 @@
     if _platform.system() == 'Darwin':
         _libname = 'libportaudio.dylib'
     elif _platform.system() == 'Windows':
+        if 'SD_ENABLE_ASIO' in _os.environ:
+            _libname = 'libportaudio' + _platform.architecture()[0] + '-asio.dll'
+        else:
+            _libname = 'libportaudio' + _platform.architecture()[0] + '.dll'
         _libname = 'libportaudio' + _platform.architecture()[0] + '.dll'
     else:
         raise