rm CPP's RT_USE_LIBC depends

Signed-off-by: SchumyHao <bob-hjl@126.com>

components/cplusplus/SConscript

@@ -6,6 +6,6 @@ cwd = GetCurrentDir()
 src = Glob('*.cpp') + Glob('*.c')
 CPPPATH = [cwd]
 
-group = DefineGroup('CPlusPlus', src, depend = ['RT_USING_CPLUSPLUS', 'RT_USING_LIBC'], CPPPATH = CPPPATH)
+group = DefineGroup('CPlusPlus', src, depend = ['RT_USING_CPLUSPLUS'], CPPPATH = CPPPATH)
 
 Return('group')