Make it easier to change the toolchain in the dualboot Makefile.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@25072 a1c6a512-1295-4272-9138-f99709370657
diff --git a/rbutil/mkamsboot/dualboot/Makefile b/rbutil/mkamsboot/dualboot/Makefile
index cc788f1..938e8a7 100644
--- a/rbutil/mkamsboot/dualboot/Makefile
+++ b/rbutil/mkamsboot/dualboot/Makefile
@@ -1,5 +1,5 @@
 CC=gcc
-
+CROSS_PREFIX=arm-elf
 # Edit the following variables (plus copy/paste another set of rules) when
 # adding a new target.  mkamsboot.c also needs to be edited to refer to these
 # new images.
@@ -12,41 +12,41 @@
 # Dualboot bootloaders
 
 dualboot_clip.o: dualboot.S
-	arm-elf-gcc -DSANSA_CLIP -c -o dualboot_clip.o dualboot.S
+	$(CROSS_PREFIX)-$(CC) -DSANSA_CLIP -c -o dualboot_clip.o dualboot.S
 
 dualboot_fuze.o: dualboot.S
-	arm-elf-gcc -DSANSA_FUZE -c -o dualboot_fuze.o dualboot.S
+	$(CROSS_PREFIX)-$(CC) -DSANSA_FUZE -c -o dualboot_fuze.o dualboot.S
 
 dualboot_e200v2.o: dualboot.S
-	arm-elf-gcc -DSANSA_E200V2 -c -o dualboot_e200v2.o dualboot.S
+	$(CROSS_PREFIX)-$(CC) -DSANSA_E200V2 -c -o dualboot_e200v2.o dualboot.S
 
 dualboot_m200v4.o: dualboot.S
-	arm-elf-gcc -DSANSA_M200V4 -c -o dualboot_m200v4.o dualboot.S
+	$(CROSS_PREFIX)-$(CC) -DSANSA_M200V4 -c -o dualboot_m200v4.o dualboot.S
 
 dualboot_c200v2.o: dualboot.S
-	arm-elf-gcc -DSANSA_C200V2 -c -o dualboot_c200v2.o dualboot.S
+	$(CROSS_PREFIX)-$(CC) -DSANSA_C200V2 -c -o dualboot_c200v2.o dualboot.S
 
 dualboot_clipv2.o: dualboot.S
-	arm-elf-gcc -DSANSA_CLIPV2 -c -o dualboot_clipv2.o dualboot.S
+	$(CROSS_PREFIX)-$(CC) -DSANSA_CLIPV2 -c -o dualboot_clipv2.o dualboot.S
 
 dualboot_clipplus.o: dualboot.S
-	arm-elf-gcc -DSANSA_CLIPPLUS -c -o dualboot_clipplus.o dualboot.S
+	$(CROSS_PREFIX)-$(CC) -DSANSA_CLIPPLUS -c -o dualboot_clipplus.o dualboot.S
 
 dualboot_fuzev2.o: dualboot.S
-	arm-elf-gcc -DSANSA_FUZEV2 -c -o dualboot_fuzev2.o dualboot.S
+	$(CROSS_PREFIX)-$(CC) -DSANSA_FUZEV2 -c -o dualboot_fuzev2.o dualboot.S
 
 # Rules for the ucl unpack function
 nrv2e_d8.o: nrv2e_d8.S
-	arm-elf-gcc -DPURE_THUMB -c -o nrv2e_d8.o nrv2e_d8.S
+	$(CROSS_PREFIX)-$(CC) -DPURE_THUMB -c -o nrv2e_d8.o nrv2e_d8.S
 
 # Rules for the ARM code embedded in mkamsboot - assemble, link, then extract
 # the binary code and finally convert to .h for building in mkamsboot
 
-%.arm-elf: %.o
-	arm-elf-ld -e 0 -Ttext=0 -o $@ $<
+%.$(CROSS_PREFIX): %.o
+	$(CROSS_PREFIX)-ld -e 0 -Ttext=0 -o $@ $<
 
-%.arm-bin: %.arm-elf
-	arm-elf-objcopy -O binary $< $@
+%.arm-bin: %.$(CROSS_PREFIX)
+	$(CROSS_PREFIX)-objcopy -O binary $< $@
 
 ../dualboot.c ../dualboot.h: $(BOOTBINS) bin2c
 	./bin2c ../dualboot $(BOOTBINS)