Add stackwalker (#117)

* Add stackwalker library

* Address issues

* Update snippet to make it more idiomatic for xmake-repo

* Try to add mingw support

* Oops

* MinGW is not supported by stackwalker (maybe we can patch this?)

* Fix debug build support

* Try to fix .patch file

* Fix version

* Fix patch checksum

packages/s/stackwalker/patches/1.20/debug_build.patch

@@ -0,0 +1,11 @@
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -4,7 +4,7 @@ cmake_minimum_required(VERSION 3.5)
+ 
+ if(NOT CMAKE_BUILD_TYPE)
+     set(CMAKE_BUILD_TYPE Release)
+-    #set(CMAKE_BUILD_TYPE Debug)
++    set(CMAKE_BUILD_TYPE Debug)
+ endif()
+ 
+ 

packages/s/stackwalker/xmake.lua

@@ -0,0 +1,36 @@
+package("stackwalker")
+
+    set_homepage("https://github.com/JochenKalmbach/StackWalker")
+    set_description("A library to walk the callstack in windows applications.")
+
+    set_urls("https://github.com/JochenKalmbach/StackWalker/archive/$(version).zip",
+             "https://github.com/JochenKalmbach/StackWalker.git")
+
+    add_versions("1.20", "b139c83b7c4991930ebe48eae43b0feedca034e136f00be294f3641495b2c835")
+    add_patches("1.20", path.join(os.scriptdir(), "patches", "1.20", "debug_build.patch"), "dcd455d9c3560bcc7793e7c2f0ffafd363f26754ae87091fb982fffcff298466")
+
+    add_deps("cmake")
+
+    if is_plat("windows") then
+        add_syslinks("advapi32")
+    end
+
+    on_install("windows", function (package)
+        local configs = {"-DStackWalker_DISABLE_TESTS=ON"}
+        table.insert(configs, "-DCMAKE_BUILD_TYPE=" .. (package:debug() and "Debug" or "Release"))
+        import("package.tools.cmake").install(package, configs)
+   end)
+
+    on_test(function (package)
+        assert(package:check_cxxsnippets({test = [[
+            void Func5() { StackWalker sw; sw.ShowCallstack(); }
+            void Func4() { Func5(); }
+            void Func3() { Func4(); }
+            void Func2() { Func3(); }
+            void Func1() { Func2(); }
+
+            void test() {
+                Func1();
+            }
+        ]]}, {includes = {"StackWalker.h"}}))
+    end)