pxpcap: Try to load platform-specific module

We now store platform-specific C++ modules in pox.lib.pxpcap.arch.pxpcap.
And we now try to load one for the current arch based on that.

There may well be a better way to do this.

pox/lib/pxpcap/__init__.py

@@ -14,11 +14,19 @@
 
 enabled = False
 try:
-  import pxpcap as pcapc
+  import platform
+  import importlib
+  _module = 'pox.lib.pxpcap.%s.pxpcap' % (platform.system().lower(),)
+  pcapc = importlib.import_module(_module)
   enabled = True
 except:
-  # We can at least import the rest
-  pass
+  # Try generic...
+  try:
+    import pxpcap as pcapc
+    enabled = True
+  except:
+    # We can at least import the rest
+    pass
 
 from pox.lib.addresses import IPAddr, EthAddr
 import parser

pox/lib/pxpcap/pxpcap_c/build_linux

@@ -1,3 +1,7 @@
 #!/bin/bash
 DEST=lib.linux*
-python setup.py build && cp build/${DEST}/pxpcap.so ..
+DEST=$(ls -d build/${DEST} | tail -1)
+OUT=../linux
+mkdir $OUT 2> /dev/null
+touch $OUT/__init__.py
+python setup.py build && cp ${DEST}/pxpcap.so .. && cp ${DEST}/pxpcap.so ${OUT}/pxpcap.so

pox/lib/pxpcap/pxpcap_c/build_mac

@@ -1,3 +1,7 @@
 #!/bin/bash
 DEST=lib.macosx*
-python setup.py build && cp build/${DEST}/pxpcap.so ..
+DEST=$(ls -d build/${DEST} | tail -1)
+OUT=../darwin
+mkdir $OUT 2> /dev/null
+touch $OUT/__init__.py
+python setup.py build && cp ${DEST}/pxpcap.so .. && cp ${DEST}/pxpcap.so ${OUT}/pxpcap.so

pox/lib/pxpcap/pxpcap_c/build_win.bat

@@ -1,13 +1,17 @@
 @echo off
 IF NOT EXIST WpdPack GOTO NODIR
 
+mkdir ..\windows
+echo. > ..\windows\__init__.py
+
 python setup.py build
 xcopy /y build\lib.win32-2.7\pxpcap.pyd ..
+xcopy /y build\lib.win32-2.7\pxpcap.pyd ..\windows
 
 GOTO DONE
 
 :NODIR
 echo Please put the WinPcap developer pack directory, WpdPack, in this directory.
 echo (You can download it from http://www.winpcap.org/devel.htm)
 
-:DONE
+:DONE