Fix scons files to use -DCGC flags correctly.

SConscript

@@ -17,7 +17,7 @@ myenv.Replace(ZIPR_SDK=os.environ['ZIPR_SDK'])
 myenv.Replace(ZIPR_INSTALL=os.environ['ZIPR_INSTALL'])
 myenv.Replace(do_cgc=ARGUMENTS.get("do_cgc",0))
 
-if 'do_cgc' in env and int(env['do_cgc']) == 1:
+if 'do_cgc' in myenv and int(myenv['do_cgc']) == 1:
         myenv.Append(CFLAGS=" -DCGC ")
         myenv.Append(CCFLAGS=" -DCGC ")