Build the dependencies

In the deps_mingw directory start by getting the submodule. 

```
deps_mingw $  git submodule update --init 
```

And then launch the dependencies build script, point the first argument to the gpac source dir cloned before: 

```
deps_mingw $  ./buildAndCopy.sh ../gpac
```

...now go grab a cup of coffee, and after a while, hopefully, all the dependencies should be built and copied in the right place in the gpac directory. 

In the gpac dir, it should look something like this: 

```
gpac $ ls extra_lib/lib/gcc/
avcodec-58.def       libfreetype.dll.a        libpng12.dll.a       libvorbis.dll.a
avdevice-58.def      libfreetype.la           libpng12.la          libvorbis.la
avfilter-7.def       libjpeg.a                libpostproc.dll.a    libvorbisenc.a
avformat-58.def      libjs.a                  libpthread.a         libvorbisenc.dll.a
avutil-56.def        libmad.a                 libpthread.dll.a     libvorbisenc.la
cmake                libmad.la                librtmp.a            libvorbisfile.a
engines-1_1          libNeptune.a             librtmp.dll.a        libvorbisfile.dll.a
fontconfig.def       libogg.a                 libSDL2.a            libvorbisfile.la
liba52.dll.a         libogg.dll.a             libSDL2.dll.a        libwinpthread.a
liba52.la            libogg.la                libSDL2.la           libwinpthread.dll.a
libaom.a             libopencore-amrnb.a      libSDL2_test.a       libwinpthread.la
libavcodec.dll.a     libopencore-amrnb.dll.a  libSDL2_test.la      libx264.a
libavdevice.dll.a    libopencore-amrnb.la     libSDL2main.a        libz.a
libavfilter.dll.a    libopencore-amrwb.a      libSDL2main.la       libz.so
libavformat.dll.a    libopencore-amrwb.dll.a  libssl.a             libz.so.1
libavutil.dll.a      libopencore-amrwb.la     libssl.dll.a         libz.so.1.2.11
libaxTLS.a           libopenhevc.a            libswresample.dll.a  libZlib.a
libcrypto.a          libopenjpeg.a            libswscale.dll.a     pkgconfig
libcrypto.dll.a      libOpenSVCDec.a          libtheora.dll.a      postproc-55.def
libexpat.dll.a       libPlatinum.a            libtheora.la         swresample-3.def
libexpat.la          libPltMediaConnect.a     libtheoradec.dll.a   swscale-5.def
libfaad.a            libPltMediaRenderer.a    libtheoradec.la      xvidcore.a
libfaad.la           libPltMediaServer.a      libtheoraenc.a       xvidcore.dll.a
libfontconfig.dll.a  libpng.dll.a             libtheoraenc.la
libfontconfig.la     libpng.la                libvorbis.a


gpac $ ls bin/gcc/
avcodec-58.dll         libfontconfig-1.dll      librtmp-1.dll        postproc-55.dll
avdevice-58.dll        libfreetype-6.dll        libssl-1_1-x64.dll   SDL2.dll
avfilter-7.dll         libogg-0.dll             libtheora-0.dll      swresample-3.dll
avformat-58.dll        libopencore-amrnb-0.dll  libtheoradec-1.dll   swscale-5.dll
avutil-56.dll          libopencore-amrwb-0.dll  libvorbis-0.dll      xvidcore.dll
liba52-0.dll           libpng12-0.dll           libvorbisenc-2.dll
libcrypto-1_1-x64.dll  libpng-3.dll             libvorbisfile-3.dll
libexpat-1.dll         librtmp.dll              libwinpthread-1.dll
```

_(contents and versions may differ depending on updates and deprecated features)_

You can pick and choose which dependency will be built by editing the file `deps_mingw/zenbuild/zen-gpacdeps.sh` and removing lines in the `gpacdeps_get_deps` function.