python3: add dtrace support

Closes #10343.

Signed-off-by: FX Coudert <fxcoudert@gmail.com>

Formula/python3.rb

@@ -4,6 +4,7 @@ class Python3 < Formula
   url "https://www.python.org/ftp/python/3.6.0/Python-3.6.0.tar.xz"
   sha256 "b0c5f904f685e32d9232f7bdcbece9819a892929063b6e385414ad2dd6a23622"
   head "https://github.com/python/cpython", :using => :git
+  revision 1
 
   bottle do
     sha256 "b9b1de457689c84376fb8c35c67b0de4745ccb573ddc5f8ce0257b3b73358917" => :sierra
@@ -85,6 +86,7 @@ class Python3 < Formula
       --datadir=#{share}
       --enable-framework=#{frameworks}
       --without-ensurepip
+      --with-dtrace
     ]
 
     args << "--without-gcc" if ENV.compiler == :clang