FFmpeg iOS build script

This is a shell script to build FFmpeg libraries for iOS and tvOS apps.

Tested with:

FFmpeg 3.2
Xcode 8

Requirements

https://github.com/libav/gas-preprocessor
yasm 1.2.0

Usage

Use build-ffmpeg-tvos.sh for tvOS.

To build everything:
```
  ./build-ffmpeg.sh
```
To build arm64 libraries:
```
  ./build-ffmpeg.sh arm64
```
To build fat libraries for armv7 and x86_64 (64-bit simulator):
```
  ./build-ffmpeg.sh armv7 x86_64
```
To build fat libraries from separately built thin libraries:
```
  ./build-ffmpeg.sh lipo
```

Download

You can download a binary for FFmpeg 3.2 release at https://downloads.sourceforge.net/project/ffmpeg-ios/ffmpeg-ios-master.tar.bz2

External libraries

You should link your app with

libz.dylib
libbz2.dylib
libiconv.dylib

Influences

https://github.com/bbcallen/ijkplayer/blob/fc70895c64cbbd20f32f1d81d2d48609ed13f597/ios/tools/do-compile-ffmpeg.sh#L7