wmcoincoin: FTBFS: ld: wmcoincoin_player.o: undefined reference to symbol 'XGetWindowAttributes'

Imported from Debian bug http://bugs.debian.org/735755:

Source: wmcoincoin
Version: 2.5.1e-1
Severity: serious
Tags: jessie sid
User: <email address hidden>
Usertags: qa-ftbfs-20140114 qa-ftbfs
Justification: FTBFS on amd64

Hi,

During a rebuild of all packages in sid, your package failed to build on
amd64.

Relevant part (hopefully):
> x86_64-linux-gnu-gcc -g -O2 -Wall -W -fsigned-char -Wno-pointer-sign -Wl,-O1 -Wl,--as-needed -rdynamic -o wmcoincoin_player fmalloc.o giffunc.o gifread.o wmcoincoin_player.o `imlib2-config --libs`
> /usr/bin/ld: wmcoincoin_player.o: undefined reference to symbol 'XGetWindowAttributes'
> //usr/lib/x86_64-linux-gnu/libX11.so.6: error adding symbols: DSO missing from command line
> collect2: error: ld returned 1 exit status

The full build log is available from:
   http://aws-logs.debian.net/ftbfs-logs/2014/01/14/wmcoincoin_2.5.1e-1_unstable.log

A list of current common problems and possible solutions is available at
http://wiki.debian.org/qa.debian.org/FTBFS . You're welcome to contribute!

About the archive rebuild: The rebuild was done on EC2 VM instances from
Amazon Web Services, using a clean, minimal and up-to-date chroot. Every
failed build was retried once to eliminate random failures.