fix spdlog (#1549)

packages/s/spdlog/xmake.lua

@@ -32,7 +32,7 @@ package("spdlog")
         if package:config("fmt_external") then
             package:add("defines", "SPDLOG_FMT_EXTERNAL")
         end
-        if package:version():ge("1.4.0") and not package:config("header_only") then
+        if not package:config("header_only") then
             package:add("deps", "cmake")
         end
         if package:config("fmt_external") then
@@ -41,7 +41,7 @@ package("spdlog")
     end)
 
     on_install(function (package)
-        if package:version():lt("1.4.0") or package:config("header_only") then
+        if (package:version() and package:version():lt("1.4.0")) or package:config("header_only") then
             os.cp("include", package:installdir())
             return
         end