[FIX] CI build error

Author: WKJay

projects/art_pi_factory/packages/btstack-v0.0.1/SConscript

@@ -56,8 +56,9 @@ path += [cwd + '/chipset/bcm']
 path += [cwd + '/port/posix-h4-bcm']
 path += [cwd + '/rtt_adapter']
 
+LOCAL_CCFLAGS = ''
 if rtconfig.CROSS_TOOL == 'keil':
-    LOCAL_CCFLAGS = ' --gnu'
+    LOCAL_CCFLAGS += ' --gnu'
 
 group = DefineGroup('RTT_BTSTACK', src, depend = [''], CPPPATH = path, LOCAL_CCFLAGS = LOCAL_CCFLAGS)