vlc-debian-win64-posix: install libgl-dev

Qt 6 GUI requires libgl-dev.

vlc-debian-win64-posix/Dockerfile

@@ -28,7 +28,7 @@ RUN set -x && \
     echo "videolan:videolan" | chpasswd && \
     apt-get update -qq && apt-get install -qqy --no-install-suggests --no-install-recommends \
         git wget bzip2 file libwine-dev unzip libtool libtool-bin libltdl-dev pkg-config ant \
-        build-essential automake texinfo ragel yasm p7zip-full autopoint \
+        build-essential automake texinfo ragel yasm p7zip-full autopoint libgl-dev \
         gettext dos2unix zip wine nsis g++-mingw-w64-i686 g++-mingw-w64-x86-64-posix mingw-w64-tools curl gperf flex bison \
         libcurl4-gnutls-dev python3 python3-venv python3-setuptools python3-mako python3-requests \
         lftp gcc make procps ca-certificates \