fix cmake flags #6781

Author: waruqi

xmake/modules/package/tools/cmake.lua

@@ -941,6 +941,11 @@ end
 function _get_configs(package, configs, opt)
     configs = configs or {}
     opt._configs_str = string.serialize(configs, {indent = false, strip = true})
+
+    -- we need to get the default flags first to avoid being overwritten.
+    -- @see https://github.com/xmake-io/xmake/issues/6781
+    local envs = _get_envs_for_default_flags(package, configs, opt)
+
     _get_configs_for_install(package, configs, opt)
     _get_configs_for_generator(package, configs, opt)
     if package:is_plat("windows") then
@@ -975,7 +980,6 @@ function _get_configs(package, configs, opt)
         table.insert(configs, "-DCMAKE_POLICY_VERSION_MINIMUM=3.5")
     end
 
-    local envs = _get_envs_for_default_flags(package, configs, opt)
     local runtime_envs = _get_envs_for_runtime_flags(package, configs, opt)
     if runtime_envs then
         envs = envs or {}