diff -up crystal-stacker-1.5/cs/source/Makefile.unix~ crystal-stacker-1.5/cs/source/Makefile.unix
--- crystal-stacker-1.5/cs/source/Makefile.unix~ 2006-04-07 10:32:26.000000000 +0200
+++ crystal-stacker-1.5/cs/source/Makefile.unix 2010-02-15 09:27:12.971926372 +0100
@@ -1,7 +1,7 @@
PREFIX = /usr/local
DATADIR = $(PREFIX)/share/$(TARGET)
CFLAGS = -g -Wall -O2 -fsigned-char
-LDFLAGS = `allegro-config --libs` -laldmb -ldumb
+LDFLAGS = `allegro-config --libs` -laldmb -ldumb -lpthread
DEFINES = -DDATADIR=\"$(DATADIR)/\"
OBJS = animate.o misc.o cs2bd.o cs2ns.o game.o keys.o \
battle.o cs.o cs2bl.o draw.o gef.o logo.o mywav.o \