Moving the elixir version check into compilation time

Author: noozo

lib/bypass/plug.ex

@@ -22,10 +22,12 @@ defmodule Bypass.Plug do
             conn
         catch
           class, reason ->
-            stacktrace = if Version.match?(System.version(), ">= 1.7.0") do
-              __STACKTRACE__
-            else
-              System.stacktrace()
+            stacktrace = unquote do
+              if Version.match?(System.version(), ">= 1.7.0") do
+                quote do: __STACKTRACE__
+              else
+                quote do: System.stacktrace()
+              end
             end
             put_result(pid, route, ref, {:exit, {class, reason, stacktrace}})
             :erlang.raise(class, reason, stacktrace)