allow specifying SRC from outside to support Visual Studio project
allow specifying SRC from outside to support Visual Studio project

LazyCodingCat/LevelDB,zao/kkowalczyk-leveldb,zao/kkowalczyk-leveldb,LazyCodingCat/LevelDB,zao/kkowalczyk-leveldb,LazyCodingCat/LevelDB,LazyCodingCat/LevelDB,zao/kkowalczyk-leveldb