[FFmpeg-trac] #7538(build system:new): Build failure for ffmpeg-4.1

[FFmpeg]

#7538: Build failure for ffmpeg-4.1
-------------------------------------+-------------------------------------
             Reporter:  PPed72       |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:  build        |                  Version:
  system                             |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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 Summary of the bug:
 Trying to build ffmpeg-4.1 on Gentoo with vaapi enabled and vdpau disabled
 fails because libX11 is not linked in.

 How to reproduce:
 # USE="vaapi -vdpau" emerge -1 ffmpeg
 [...]
 x86_64-pc-linux-gnu-gcc -Llibavcodec -Llibavdevice -Llibavfilter
 -Llibavformat -Llibavresample -Llibavutil -Llibpostproc -Llibswscale
 -Llibswresample -Wl,-O1 -Wl,--as-needed -Wl,--hash-style=gnu -Wl,--sort-
 common -flto=8  -march=sandybridge -Wl,--as-needed -Wl,-z,noexecstack -Wl
 ,--warn-common -Wl,-rpath-
 link=libpostproc:libswresample:libswscale:libavfilter:libavdevice:libavformat:libavcodec:libavutil:libavresample
 -O2 -pipe -march=sandybridge -msahf --param l1-cache-size=32 --param l1
 -cache-line-size=64 --param l2-cache-size=8192 -flto=8 -fno-math-errno
 -fno-signed-zeros -flto -march=sandybridge -fno-tree-vectorize  -o
 tools/aviocat tools/aviocat.o -lavformat -lavcodec -lswresample -lavutil
 -lm -lbz2 -lgmp -lz -lssl -lcrypto -lssh -lsmbclient -lvpx -lm -lvpx -lm
 -lvpx -lm -lvpx -lm -lwebpmux -lwebp -pthread -lm -llzma -lopencore-amrwb
 -lrsvg-2 -lm -lgio-2.0 -lgdk_pixbuf-2.0 -lgobject-2.0 -lglib-2.0 -lcairo
 -lz -lfdk-aac -lmp3lame -lm -lopencore-amrnb -lopenjp2 -lopus -lspeex
 -ltheoraenc -ltheoradec -logg -lvorbis -lvorbisenc -lwebp -lx264 -lx265
 -lxvidcore -lkvazaar -lva -lm -lsoxr -pthread -lva-drm -lva -lva-x11 -lva
 -lm -lva
 libavutil/libavutil.so: error: undefined reference to 'XCloseDisplay'
 libavutil/libavutil.so: error: undefined reference to 'XDisplayName'
 libavutil/libavutil.so: error: undefined reference to 'XOpenDisplay'
 collect2: error: ld returned 1 exit status

 Reverting commit
 https://git.ffmpeg.org/gitweb/ffmpeg.git/commit/a00763be8861bcf499675b2af89d29e4e113cdc9

 fixes the issue for me.

 Gentoo bug is: https://bugs.gentoo.org/670590

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Ticket URL: <https://trac.ffmpeg.org/ticket/7538>
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