On 21 May 2014 03:16, <rongqing.li at windriver.com> wrote: > $CC is able to has ',', when $CC includes some flags, Presumably you're referring to flags such as -Wl,-O1. Shouldn't these flags be set in CPPFLAGS/CFLAGS/LDFLAGS, or can you give an example of where they need to be set in CC. Ross