r14326 added '-Wno-unused-result' to 'WARNING_CFLAGS!' which removes the flag. This change moves it to WARNING_CFLAGS, and makes it work for both iOS and mac.
r14326 added '-Wno-unused-result' to 'WARNING_CFLAGS!' which removes the
flag. This change moves it to WARNING_CFLAGS, and makes it work for both
iOS and mac.

BUG=webrtc:6396
NOTRY=True
NOPRESUBMIT=True
NOTREECHECKS=True

Review-Url: https://codereview.webrtc.org/2369803002
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#14378}

TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc