makefile: link Lua objects into libcallisto

Fixes: https://todo.sr.ht/~jeremy/callisto/13

configure

@@ -130,6 +130,14 @@ gen_LDFLAGS () {
 	ldflags="$(trim "$ldflags")"
 }
 
+## Lua objects
+gen_LUAOBJS () {
+	for obj in $(make -Cexternal/lua -s echo | grep -E '^BASE_O= ' | cut -d " " -f2-); do
+		luaobjs="$luaobjs external/lua/$obj"
+	done
+	luaobjs="$(trim "$luaobjs")"
+}
+
 #
 ## misc. functions
 #
@@ -197,6 +205,7 @@ cd $(dirname $0)
 gen_CC
 gen_CFLAGS
 gen_LDFLAGS
+gen_LUAOBJS
 
 printf '# generated by configure
 
@@ -206,10 +215,13 @@ _CPPFLAGS = %s
 _LDFLAGS  =%s
 
 _EXT_CPPFLAGS = %s
+
+_LUAOBJS = %s
 '              \
 	"$cc"      \
 	"$cflags"  \
 	"$cppflags"\
 	"$ldflags" \
 	"$ext_cppflags"\
+	"$luaobjs"\
 		>"$mkf"