diff --git a/configure.in b/configure.in
index 5f09561..367049a 100644
--- a/configure.in
+++ b/configure.in
@@ -23,6 +23,14 @@ dnl AC_SUBST(CFLAGS, "$CFLAGS -I${scsh_includes}")
 dnl AC_CHECK_HEADER([scheme48.h], [], 
 dnl 		AC_MSG_FAILURE("Could not find scheme48.h"))
 
+AC_ARG_WITH(ffi-tools,
+	    AC_HELP_STRING([--with-ffi-tools=DIR],
+		 	   [where to find ffi-tools.c and ffi-tools.h [/usr/local/include]]),
+			   ffi_tools_prefix=$withval,
+			   ffi_tools_prefix=/usr/local/include)
+AC_SUBST(ffi_tools_prefix)
+AC_SUBST(CFLAGS, "$CFLAGS -I${ffi_tools_prefix}")
+
 AC_PATH_PROG([SCSH], [scsh], [-not found-], [$PATH])
 if test "$SCSH" = "-not found-"; then
   AC_MSG_FAILURE("No scsh binary in path")