There are lots of places where we add flags to both the C[{C,XX}]FLAGS and [SH]LINKFLAGS, because these flags need to be present for both tasks. Generally, we do this on platforms that use clang/gcc, since there we invoke the compiler to drive the link. So flags that affect both compile and link should appear in both. It would be easier if we just always included C[{C,XX}]FLAGS on the link line, and then we wouldn't need to add the flags in two places.