Fix s7 link error on Linux (#2119)

Co-authored-by: 沈浪熊猫儿 <[email protected]>

packages/s/s7/port/xmake.lua

@@ -39,4 +39,7 @@ target("s7") do
     if not is_plat("macosx") then
         add_ldflags("-static", "-static-libgcc", {force = true})
     end
+    if is_plat("linux") then
+        add_syslinks("pthread", "dl")
+    end
 end