minizip: xmake version check error (#8403)

* minizip: xmake version check error

Within the on_install environment, xmake.version does not exists.

* minizip: Refactor version check variable for clarity

* minizip: xmake version check error

packages/m/minizip/xmake.lua

@@ -76,7 +76,7 @@ package("minizip")
             local configs = {}
             configs.bzip2 = package:config("bzip2")
             os.cp(path.join(package:scriptdir(), "port", "xmake.lua"), "xmake.lua")
-            import("package.tools.xmake").install(package, configs)
+            import("package.tools.xmake", {anonymous = true}).install(package, configs)
 
             local config_version_file = path.join(package:installdir("lib"), "cmake", "minizip", "minizipConfigVersion.cmake")
             if xmake:version():lt("3.0.4") and package:is_plat("cross") and package:check_sizeof("void*") == "4" and os.exists(config_version_file) then