Well, you should not send the poor guy to left and right at the same time

...
Ok, agreed.
The mouse shows up as white box. Same size as cursor and fully functional.
In the meantime I found the place where game stops for me.
The error message is: "There are not enought :'s in mp_data/wawalite.txt"
I traced it down to read_wawalight_fog where it reads fog.bottom.
Here's the stack trace:
[spoiler]
(gdb) where
#0 sys_popup (popup_title=<value optimized out>, warning=<value optimized out>, format=0x49b9d0 "There are not enough %c's in file! (%s)\n", args=<value optimized out>) at platform/sys_linux.c:76
#1 0x0000000000451b19 in log_error (format=0x49b9d0 "There are not enough %c's in file! (%s)\n") at log.c:155
#2 0x0000000000429791 in goto_delimiter (buffer=0x0, fileread=0x2b0ca80, delim=58 ':', optional=bfalse) at egoboo_fileutil.c:145
#3 0x000000000042a4e6 in fget_next_float (fileread=0x2b0ca80) at egoboo_fileutil.c:872
#4 0x0000000000493487 in read_wawalite_fog (filename=<value optimized out>, pdata=0x1ad04d0) at file_formats/wawalite_file.c:310
#5 read_wawalite_file_vfs (filename=<value optimized out>, pdata=0x1ad04d0) at file_formats/wawalite_file.c:368
#6 0x0000000000438e75 in read_wawalite () at game.c:4825
#7 0x0000000000439198 in game_load_module_assets (modname=0x7fff301bf3d0 "mp_modules/advent.mod/") at game.c:3161
#8 0x000000000043927a in game_load_module_data (modname=0x1b004e0 "mp_modules/advent.mod", seed=1298501898) at game.c:3221
#9 game_begin_module (modname=0x1b004e0 "mp_modules/advent.mod", seed=1298501898) at game.c:3468
#10 0x000000000043b3e2 in do_game_proc_begin (gproc=0x18cb3a0, frameDuration=<value optimized out>) at game.c:1070
#11 do_game_proc_run (gproc=0x18cb3a0, frameDuration=<value optimized out>) at game.c:1334
#12 0x0000000000487348 in do_ego_proc_running (argc=<value optimized out>, argv=<value optimized out>) at egoboo.c:304
#13 SDL_main (argc=<value optimized out>, argv=<value optimized out>) at egoboo.c:435
#14 0x00007fec6f63ab7d in __libc_start_main () from /lib64/libc.so.6
#15 0x0000000000406529 in _start () at ../sysdeps/x86_64/elf/start.S:113
[/spoiler]