diff --git a/xtrn/sbl/Makefile b/xtrn/sbl/Makefile
index 8dde8c881e323881042338aec65609786bdd663a..eac5f3b57763f932e3bdae99bebb91d4f7f74f93 100644
--- a/xtrn/sbl/Makefile
+++ b/xtrn/sbl/Makefile
@@ -8,14 +8,18 @@
 CC		=	bcc32
 LD		=	ilink32
 XSDK	= ..\sdk
+!ifndef SRC_ROOT
+	SRC_ROOT=	..\..\src
+!endif
+
 !ifndef XPDEV
- XPDEV		=	../../src/xpdev
+ XPDEV		=	$(SRC_ROOT)\xpdev
 !endif
 !ifndef SBBS_SRC
- SBBS_SRC	=	../../src/sbbs3
+ SBBS_SRC	=	$(SRC_ROOT)\sbbs3
 !endif
 !ifndef SMBLIB_SRC
- SMBLIB_SRC	=	../../src/smblib
+ SMBLIB_SRC	=	$(SRC_ROOT)\smblib
 !endif
 
 CFLAGS	= -WM -I$(XSDK);$(XPDEV);$(SBBS_SRC);$(SMBLIB_SRC)