gn: Fix cflags usage

R=brettw@chromium.org
TBR=kjellander@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/29519004

Patch from Cem Kocagil <ckocagil@chromium.org>.

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7198 4adac7df-926f-26a2-2b94-8c16560cd09d
Add a gyp target for producing a voice engine merged library.

This is based on webrtc/build/merge_libs.gyp, with a dependency on
voice_engine.gyp instead and suitable name changes.

Executing:
$ rm -rf out/
$ ./webrtc/build/gyp_webrtc -Denable_video=0 -Denable_protobuf=0
-Drelease_optimize=s webrtc/build/merge_libs_voice.gyp
$ ninja -C out/Release merged_lib_voice

results in a minimially sized voice engine lib at:
out/Release/librtc_voice_merged.a

Linux: 6.4 MB
Mac: 3.7 MB

R=braveyao@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/23659004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7199 4adac7df-926f-26a2-2b94-8c16560cd09d
Implemented Network::GetBestIP() selection logic as following.

1) return the first global temporary and non-deprecrated ones.
2) if #1 not available, return global one.
3) if #2 not available, use ULA ipv6 as last resort.

ULA stands for unique local address. They are only useful in a private
WebRTC deployment. More detail: http://en.wikipedia.org/wiki/Unique_local_address

BUG=3808

At this point, rule #3 actually won't happen at current
implementation. The reason being that ULA address starting with 0xfc 0r 0xfd will be grouped into its own Network. The result of that is WebRTC will have one extra Network to generate candidates but the lack of rule #3 shouldn't prevent turning on IPv6 since ULA should only be tried in a close deployment anyway.

R=jiayl@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/31369004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7200 4adac7df-926f-26a2-2b94-8c16560cd09d
Implemented Network::GetBestIP() selection logic as following.

1) return the first global temporary and non-deprecrated ones.
2) if #1 not available, return global one.
3) if #2 not available, use ULA ipv6 as last resort.

ULA stands for unique local address. They are only useful in a private
WebRTC deployment. More detail: http://en.wikipedia.org/wiki/Unique_local_address

BUG=3808

At this point, rule #3 actually won't happen at current
implementation. The reason being that ULA address starting with 0xfc 0r 0xfd will be grouped into its own Network. The result of that is WebRTC will have one extra Network to generate candidates but the lack of rule #3 shouldn't prevent turning on IPv6 since ULA should only be tried in a close deployment anyway.

R=jiayl@webrtc.org

Committed: https://code.google.com/p/webrtc/source/detail?r=7200

Review URL: https://webrtc-codereview.appspot.com/31369004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7201 4adac7df-926f-26a2-2b94-8c16560cd09d