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

Sconscript

@@ -1,11 +1,9 @@
-Import('rtconfig')
-import os
 from building import *
 
 cwd = GetCurrentDir()
 src = ['sqlite3.c']
-CPPPATH = [cwd, str(Dir('#'))]
+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')