diff --git a/src/lisp/Jmk b/src/lisp/Jmk
index 42a0e51..d5d3001 100644
--- a/src/lisp/Jmk
+++ b/src/lisp/Jmk
@@ -1,5 +1,9 @@
+# -*- mode:makefile -*-
+
 init(lisp, lisp)
 
+option(PLAT, "`platform to build for: either linux or bluejay'", linux)
+
 preset(optimize)
 preset(32)
 preset(debug)
@@ -13,6 +17,12 @@
 			lisp.o \
 			compiler.o
 
+ifeq ($(PLAT),linux)
+OBJECTS += plat/linux.o
+else
+$(error linux is the only supported option for PLAT)
+endif
+
 LUA = vendor/luajit/src/host/minilua
 
 vendor/luajit/src/host/minilua: vendor/luajit/src/host/minilua.c