davs2 and xavs2 not support ios compile

[tonypccheny]

I want use davs2 and xavs2 on ios platform,but there is little information on configure for arm64 armv7 armv7s x86_64 i386 of ios platform compile needs.Is there someone can help me,thanks very much!

[luofalei]

@tonypccheny We haven't tried the IOS platform before and currently I don't have an IOS based phone for test. xavs2 and davs2 could be built for Android platform. A script build/linux/android_build.sh had been added in this repository. I think you can check this script and modify it for IOS. If there are some building errors to be fixed, it's good to make pull requests to make it fixed. Thank you!