Merge pull request #2 from SummerGGift/master

[修改]：增加sqlite包依赖'RT_USING_DFS',去除不需要的代码。

Sconscript

@@ -4,6 +4,6 @@ cwd = GetCurrentDir()
 src = ['sqlite3.c']
 CPPPATH = [cwd]
 
-group = DefineGroup('sqlite', src, depend = ['RT_USING_SQLITE'], CPPPATH = CPPPATH)
+group = DefineGroup('sqlite', src, depend = ['RT_USING_DFS', 'PKG_USING_SQLITE'], CPPPATH = CPPPATH)
 
-Return('group')
+Return('group')