lua checks

stepmania/autoconf/m4/lua.m4

@@ -0,0 +1,33 @@
+AC_DEFUN(SM_LUA, [
+
+AC_CHECK_PROGS(LUA_CONFIG, [lua-config50 lua-config], "")
+if test "$LUA_CONFIG" != ""; then
+	LUA_CFLAGS=`lua-config --include`
+	LUA_LIBS=`lua-config --static`
+else
+	LUA_CFLAGS=
+	LUA_LIBS=
+	if test "$LIB_LUA" = ""; then
+		AC_CHECK_LIB(lualib, lua_open, LIB_LUA=-llua)
+	fi
+	if test "$LIB_LUA" = ""; then
+		AC_CHECK_LIB(lua50, lua_open, LIB_LUA=-llua50)
+	fi
+	if test "$LIB_LUA_LIB" = ""; then
+		AC_CHECK_LIB(lualib, luaopen_base, LIB_LUA_LIB=-llualib, , [$LIB_LUA])
+	fi
+	if test "$LIB_LUA_LIB" = ""; then
+		AC_CHECK_LIB(lualib50, luaopen_base, LIB_LUA_LIB=-llualib50, , [$LIB_LUA])
+	fi
+	if test "$LIB_LUA" = "" -o "$LIB_LUA_LIB" = ""; then
+		echo
+		echo "*** liblua is required to build StepMania; please"
+		echo "*** make sure that liblua is installed to continue"
+		echo "*** the installation process."
+		exit 0;
+	fi
+fi
+AC_SUBST(LUA_CFLAGS)
+AC_SUBST(LUA_LIBS)
+
+])