GCC BATARD!!!
public text v1 · immutable:~/Desktop/TP_SCA$ gcc -L/usr/X11R6/lib -lMrm -lXm -lXt -lXp -lXext -lX11 paint.c callback.c INITIALISATION.C
/tmp/ccYvuIUz.o: In function `main':
paint.c:(.text+0x1eb): undefined reference to `initialisation'
/tmp/ccsD41Cw.o:(.eh_frame+0x11): undefined reference to `__gxx_personality_v0'
collect2: ld returned 1 exit status