Re: WIP SDL packages

[Ludovic Courtès]

Commit 558a512 makes libx11 a propagated input, which seemed to be the
right thing.

I added SDL as an input for QEMU.  Now, when run directly, it just fails:

  Could not initialize SDL(No available video device) - exiting

Looking at strace, I found that it actually needed this:

  LD_LIBRARY_PATH=$(guix build libxext)/lib qemu-system-x86_64 ...

IOW it dlopen’s libXext by default.  To avoid the trouble, I think SDL
should either (1) have libXext in its RUNPATH, or (2) be explicitly
linked against it (which is essentially equivalent.)

WDYT?  Would you like to make that change?

Thanks,
Ludo’.