Index: kernel/arch/amd64/Makefile.inc
===================================================================
--- kernel/arch/amd64/Makefile.inc	(revision da349da00e6a694ae8529efd7efc34b7534e322f)
+++ kernel/arch/amd64/Makefile.inc	(revision 3771a6e7731d68e45b150595dd2c0f6ba32df887)
@@ -30,9 +30,13 @@
 #
 
+ifndef CROSS_PREFIX
+	CROSS_PREFIX = /usr/local
+endif
+
 BFD_NAME = elf64-x86-64
 BFD_ARCH = i386:x86-64
 BFD = binary
 TARGET = amd64-linux-gnu
-TOOLCHAIN_DIR = /usr/local/amd64
+TOOLCHAIN_DIR = $(CROSS_PREFIX)/amd64
 
 FPU_NO_CFLAGS = -mno-sse -mno-sse2