stand: consolidate knowledge of lua path

Multiple places coordinate to 'know' where lua scripts are installed. Knock
this down to being formally defined (and overridable) in exactly one spot,
defs.mk, and spread the knowledge to loaders and liblua alike. A future
commit will expose this to lua as loader.lua_path, so it can build absolute
paths to lua scripts as needed.

MFC after:	1 week

stand/common/interp_lua.c

@@ -60,6 +60,8 @@ static struct interp_lua_softc lua_softc;
 #define	LDBG(...)
 #endif
 
+#define	LOADER_LUA	LUA_PATH "/loader.lua"
+
 INTERP_DEFINE("lua");
 
 static void *
@@ -120,7 +122,7 @@ interp_init(void)
 		lua_pop(luap, 1);  /* remove lib */
 	}
 
-	filename = "/boot/lua/loader.lua";
+	filename = LOADER_LUA;
 	if (interp_include(filename) != 0) {
                 const char *errstr = lua_tostring(luap, -1);
                 errstr = errstr == NULL ? "unknown" : errstr;

stand/defs.mk

@@ -40,6 +40,9 @@ BOOTOBJ=	${OBJTOP}/stand
 # BINDIR is where we install
 BINDIR?=	/boot
 
+# LUAPATH is where we search for and install lua scripts.
+LUAPATH?=	/boot/lua
+
 LIBSA=		${BOOTOBJ}/libsa/libsa.a
 .if ${MACHINE} == "i386"
 LIBSA32=	${LIBSA}

stand/liblua/Makefile

@@ -27,7 +27,7 @@ SRCS+=	lerrno.c lfs.c lstd.c lutils.c
 
 WARNS=	3
 
-CFLAGS+= -DLUA_PATH_DEFAULT=\"/boot/lua/\?.lua\"
+CFLAGS+= -DLUA_PATH=\"${LUAPATH}\" -DLUA_PATH_DEFAULT=\"${LUAPATH}/\?.lua\"
 CFLAGS+= -ffreestanding -nostdlib -DLUA_USE_POSIX
 CFLAGS+= -fno-stack-protector -D__BSD_VISIBLE
 CFLAGS+= -I${BOOTSRC}/include -I${LIBLUASRC} -I${LUASRC} -I${LDRSRC}

stand/liblua/luaconf.h

@@ -202,7 +202,7 @@
 
 #else			/* }{ */
 
-#define LUA_ROOT       "/boot/lua/" LUA_VDIR "/"
+#define LUA_ROOT       LUA_PATH "/" LUA_VDIR "/"
 #define LUA_LDIR       LUA_ROOT "share/"
 #define LUA_CDIR       LUA_ROOT "lib/"
 #ifndef LUA_PATH_DEFAULT

stand/loader.mk

@@ -62,6 +62,7 @@ SRCS+=	interp_lua.c
 .include "${BOOTSRC}/lua.mk"
 LDR_INTERP=	${LIBLUA}
 LDR_INTERP32=	${LIBLUA32}
+CFLAGS+= -DLUA_PATH=\"${LUAPATH}\"
 .elif ${LOADER_INTERP} == "4th"
 SRCS+=	interp_forth.c
 .include "${BOOTSRC}/ficl.mk"

stand/lua/Makefile

@@ -12,7 +12,7 @@ MAN=	cli.lua.8 \
 	password.lua.8 \
 	screen.lua.8
 
-FILESDIR=	/boot/lua
+FILESDIR=	${LUAPATH}
 FILES=	cli.lua \
 	color.lua \
 	config.lua \