Update depend

SConscript

@@ -6,6 +6,6 @@ cwd = GetCurrentDir()
 src = Glob('src/*.c') + Glob('src/*.cpp')
 CPPPATH = [cwd + '/include']
 
-group = DefineGroup('TinyCrypt', src, depend = [], CPPPATH = CPPPATH)
+group = DefineGroup('TinyCrypt', src, depend = ['PKG_USING_TINYCRYPT'], CPPPATH = CPPPATH)
 
 Return('group')