improve gtest

packages/g/gtest/xmake.lua

@@ -9,13 +9,21 @@ package("gtest")
     add_versions("archive:1.8.1", "927827c183d01734cc5cfef85e0ff3f5a92ffe6188e0d18e909c5efebf28a0c7")
 
     on_install(function (package)
-        os.cp("./googletest/include", package:installdir())
+        io.writefile("xmake.lua", [[
+            target("gtest")
+                set_kind("static")
+                add_files("googletest/src/gtest-all.cc")
+                add_includedirs("googletest/include", "googletest")
+                add_headerfiles("googletest/include/(**.h)")
+        ]])
+        import("package.tools.xmake").install(package)
     end)
 
     on_test(function (package)
         assert(package:check_cxxsnippets({test = [[
             int factorial(int number) { return number <= 1 ? number : factorial(number - 1) * number; }
             TEST(FactorialTest, Zero) {
+              testing::InitGoogleTest(0, (char**)0);
               EXPECT_EQ(1, factorial(1));
               EXPECT_EQ(2, factorial(2));
               EXPECT_EQ(6, factorial(3));