build steps on Scientific Linux 6 (To support old glibc versions)
* build nasm-2.13.01.tar.xz
  * tar -xvf nasm-2.13.01.tar.xz
  * cd nasm-2.13.01
  * ./configure
  * make
  * as root: make install
* build libav-12.3.tar.xz
  * tar -xvf libav-12.3.tar.xz
  * cd libav-12.3
  * ./configure --enable-static --disable-debug
  * make
  * als root: make install
* build x264-snapshot-20190707-2245-stable.tar
  * tar -zxvf x264-snapshot-20190707-2245-stable.tar.gz
  * cd x264-snapshot-20190707-2245-stable
  * ./configure --enable-static 
  * make
* build gpac-master.zip
  * unzip gpac-master.zip
  * cd gpac-master
  * ./configure --static-mp4box --use-zlib=no
  * make
