Mine

CFLAGS+= -Wall -pipe -O3 -fexpensive-optimizations
LDFLAGS+= -Lxpm-3.4g -L/usr/X11R6/lib -lXpm -lX11

.PHONY: thelibrary clean

xdemineur: thelibrary xdemineur.o main.o demineur.o util.o
xdemineur.o:
main.o:
demineur.o:
util.o:

thelibrary:
    $(MAKE) -C xpm-3.4g MAKEFLAGS=
clean:
    rm -f *.o *~
    $(MAKE) -C xpm-3.4g clean