Delete the unused '--keep' link flag when used RT_USED marco.

src/SConscript

@@ -5,15 +5,6 @@ from building import *
 src = Glob('*.c')
 
 CPPPATH = [RTT_ROOT + '/include']
-if rtconfig.CROSS_TOOL == 'keil':
-    # add more link flags for module and components_init.
-    LINKFLAGS = ''
-    if GetDepend('RT_USING_MODULE'):
-        LINKFLAGS += ' --keep *.o(RTMSymTab) '
-    if GetDepend('RT_USING_COMPONENTS_INIT'):
-        LINKFLAGS += ' --keep *.o(.rti_fn.*) '
-else:
-    LINKFLAGS = ''
 
 if GetDepend('RT_USING_COMPONENTS_INIT') == False:
     SrcRemove(src, ['components.c'])
@@ -38,6 +29,6 @@ if GetDepend('RT_USING_MEMHEAP') == False:
 if GetDepend('RT_USING_DEVICE') == False:
     SrcRemove(src, ['device.c'])
 
-group = DefineGroup('Kernel', src, depend = [''], CPPPATH = CPPPATH, LINKFLAGS = LINKFLAGS)
+group = DefineGroup('Kernel', src, depend = [''], CPPPATH = CPPPATH)
 
 Return('group')