iOS ijkplayer替换ffmpeg4.0内核-2019-03-26

1.所以要改动，只需要把IJK_FFMPEG_COMMIT=ff3.4--ijk0.8.7--20180103--001换成JK_FFMPEG_COMMIT=ff4.0--ijk0.8.25--20181123--001就可以，然后再做验证性测试。

https://www.jianshu.com/p/367ae20c2db8

2.其他事项备忘

（1）如下图，修改do-compile-ffmpeg.sh和compile-ffmpeg.sh脚本，添加libx264支持。将编译好的libx264

(2)./compile--ffmpeg.sh armv7编译报错问题：
audio_convert_neon.S:25:1: error: invalid symbol redefinition

_swri_oldapi_conv_flt_to_s16_neon:

解决方案：
https://github.com/DeviLeo/DLGPlayer/issues/19
https://react.ctolib.com/DeviLeo-DLGPlayer.html
Delete _swri_oldapi_conv_flt_to_s16_neon: and _swri_oldapi_conv_fltp_to_s16_2ch_neon:.

Change _swri_oldapi_conv_flt_to_s16_neon to X(swri_oldapi_conv_flt_to_s16_neon) and _swri_oldapi_conv_fltp_to_s16_2ch_neon to X(swri_oldapi_conv_fltp_to_s16_2ch_neon).