build failing with latest gcc (user_readline.c:49:31: error: assignment from incompatible pointer type)

[anthraxx]

when building with gcc 6.2.1 I'm getting the following error:

[ 26%] Building C object lib/haka/CMakeFiles/libhaka.dir/luadebug/user_readline.c.o
/build/haka-git/src/haka-git/lib/haka/luadebug/user_readline.c: In function 'start':
/build/haka-git/src/haka-git/lib/haka/luadebug/user_readline.c:49:31: error: assignment from incompatible pointer type [-Werror=incompatible-pointer-types]
  rl_completion_entry_function = empty_generator;
                               ^
cc1: all warnings being treated as errors
make[2]: *** [lib/haka/CMakeFiles/libhaka.dir/build.make:934: lib/haka/CMakeFiles/libhaka.dir/luadebug/user_readline.c.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:1059: lib/haka/CMakeFiles/libhaka.dir/all] Error 2
make: *** [Makefile:161: all] Error 2
==> ERROR: A failure occurred in build().
    Aborting...

[paulfariello]

Just encountered the exact same issue.
Try d6ee4d2 if you need a temporary patch.