Fix 'unresolved external symbol' errors on Windows.
Fix 'unresolved external symbol' errors on Windows.

* build/gen_def.py
  (main): Blacklist the serf v2 API, these aren't implemented yet.
  
SirJson/serf,zhupan/serf,lazysoez/serf,pengdu/serf,soufianeEL/serf,x-clone/serf,zhengcq315/serf,stoneCC/serf,zhengcq315/serf,alex1818/serf,stoneCC/serf,stoneCC/serf,x-clone/serf,lazysoez/serf,google-code-export/serf,lazysoez/serf,lazysoez/serf,alex1818/serf,KyleSanderson/serf,SirJson/serf,stoneCC/serf,google-code-export/serf,yesoce/serf,KyleSanderson/serf,zhengcq315/serf,KyleSanderson/serf,pengdu/serf,zhupan/serf,zhengcq315/serf,soufianeEL/serf,KyleSanderson/serf,pengdu/serf,x-clone/serf,zhupan/serf,yesoce/serf,zhupan/serf,alex1818/serf,soufianeEL/serf,yesoce/serf,soufianeEL/serf,google-code-export/serf,pengdu/serf,SirJson/serf,yesoce/serf,SirJson/serf,google-code-export/serf,x-clone/serf,alex1818/serf