add lib32 target to build a 32 bit library on 64 bit systems

Makefile

@@ -2,6 +2,13 @@
 #a Parallel Cable III
 CFLAGS=-Wall -fPIC -DUSB_DRIVER_VERSION="\"$(shell stat -c '%y' usb-driver.c |cut -d\. -f1)\"" #-DFORCE_PC3_IDENT
 
+MARCH := $(shell uname -m)
+ifeq ($(MARCH),x86_64)
+CFLAGS += -m64
+else
+CFLAGS += -m32
+endif
+
 FTDI := $(shell libftdi-config --libs 2>/dev/null)
 ifneq ($(FTDI),)
 JTAGKEYSRC = jtagkey.c
@@ -11,12 +18,18 @@ endif
 SOBJECTS=libusb-driver.so libusb-driver-DEBUG.so
 
 all: $(SOBJECTS)
+ifeq ($(MARCH),x86_64)
+	@echo Built library is 64 bit. Run \`make lib32\' to build a 32 bit version
+endif
 
 libusb-driver.so: usb-driver.c parport.c jtagkey.c config.c jtagmon.c usb-driver.h parport.h jtagkey.h config.h jtagmon.h Makefile
-	gcc $(CFLAGS) usb-driver.c parport.c config.c jtagmon.c $(JTAGKEYSRC) -o $@ -ldl -lusb -lpthread $(FTDI) -shared
+	$(CC) $(CFLAGS) usb-driver.c parport.c config.c jtagmon.c $(JTAGKEYSRC) -o $@ -ldl -lusb -lpthread $(FTDI) -shared
 
 libusb-driver-DEBUG.so: usb-driver.c parport.c jtagkey.c config.c jtagmon.c usb-driver.h parport.h jtagkey.h config.h jtagmon.h Makefile
-	gcc -DDEBUG $(CFLAGS) usb-driver.c parport.c config.c jtagmon.c $(JTAGKEYSRC) -o $@ -ldl -lusb -lpthread $(FTDI) -shared
+	$(CC) -DDEBUG $(CFLAGS) usb-driver.c parport.c config.c jtagmon.c $(JTAGKEYSRC) -o $@ -ldl -lusb -lpthread $(FTDI) -shared
+
+lib32:
+	$(MAKE) MARCH=i386 clean all
 
 clean:
 	rm -f $(SOBJECTS)