When I tried to simply emerge vlc via sudo emerge -a vlc i got the following error:
The following REQUIRED_USE flag constraints are unsatisfied:
httpd? ( lua )
The above constraints are a subset of the following complete expression:
aalib? ( X ) bidi? ( truetype ) cddb? ( cdda ) dvb? ( dvbpsi ) dxva2? ( avcodec ) ffmpeg? ( avcodec avformat swscale ) fontconfig? ( truetype ) gnutls? ( gcrypt ) httpd? ( lua ) libcaca? ( X ) libtar? ( skins ) libtiger? ( kate ) qt4? ( X !qt5 ) qt5? ( X !qt4 ) sdl? ( X ) skins? ( truetype X exactly-one-of ( qt4 qt5 ) ) vaapi? ( avcodec X ) vlm? ( encode ) xv? ( xcb )
First i had no idea what this lines meant, but it seams that if you want to use httpd you need also lua.
On videolan.org they give an advice for the minimal set of useflags for the vlc ebuild.
I ended up adding two lines to /etc/portage/package.use:
media-video/vlc dvd ffmpeg mpeg mad wxwindows aac dts a52 ogg flac theora oggvorbis matroska freetype bidi xv svga gnutls stream vlm httpd cdda vcd cdio live vaapi -qt4 qt5 avahi lua directfb opus samba sdl sdl-image
media-video/ffmpeg vaapi opus samba sdl -ieee1394
I had a problem to build the lib for firewire which was a depency for ffmpeg. Since I have no firewire device I just droped it and removed the default useflag ieee1394.