[gcc] add footprint information when compiling

Author: mysterywolf

src/SConscript

@@ -30,8 +30,10 @@ else:
     SrcRemove(src, ['scheduler_up.c'])
 
 LOCAL_CFLAGS = ''
+LINKFLAGS = ''
 
 if rtconfig.PLATFORM in ['gcc']: # only for GCC
+    LINKFLAGS += ' -Wl,--gc-sections,--print-memory-usage' # remove unused sections and print memory usage
     LOCAL_CFLAGS += ' -Wunused' # unused warning
     LOCAL_CFLAGS += ' -Wformat -Wformat-security' # printf/scanf format warning
     LOCAL_CFLAGS += ' -Warray-bounds -Wuninitialized' # memory access warning
@@ -42,6 +44,8 @@ if rtconfig.PLATFORM in ['gcc']: # only for GCC
         LOCAL_CFLAGS += ' -Wimplicit-fallthrough' # implicit fallthrough warning
         LOCAL_CFLAGS += ' -Wduplicated-cond -Wduplicated-branches' # duplicated condition warning
 
-group = DefineGroup('Kernel', src, depend=[''], CPPPATH=inc, CPPDEFINES=['__RTTHREAD__'], LOCAL_CFLAGS=LOCAL_CFLAGS, LOCAL_CPPDEFINES=['__RT_KERNEL_SOURCE__'])
+group = DefineGroup('Kernel', src, depend=[''], CPPPATH=inc,
+                    LINKFLAGS=LINKFLAGS, LOCAL_CFLAGS=LOCAL_CFLAGS,
+                    CPPDEFINES=['__RTTHREAD__'], LOCAL_CPPDEFINES=['__RT_KERNEL_SOURCE__'])
 
 Return('group')