Add extsources to bzip2 (#1347)

* Update xmake.lua

* Update xmake.lua

packages/b/bzip2/xmake.lua

@@ -6,7 +6,15 @@ package("bzip2")
     add_urls("https://sourceware.org/pub/bzip2/bzip2-$(version).tar.gz")
     add_versions("1.0.8", "ab5a03176ee106d3f0fa90e381da478ddae405918153cca248e682cd0c4a2269")
 
-    on_install(function (package)
+    if is_plat("mingw") and is_subhost("msys") then
+        add_extsources("pacman::bzip2")
+    elseif is_plat("linux") then
+        add_extsources("pacman::bzip2", "apt::libbz2-dev")
+    elseif is_plat("macosx") then
+        add_extsources("brew::bzip2")
+    end
+
+    on_install("linux", "macosx", "windows", "android", "iphoneos", "cross", "bsd", "mingw", function (package)
         local configs = {}
         if not package:is_plat("cross", "iphoneos", "android") then
             configs.enable_tools = true