From 2019f0c9f5a5b5469e65effbd9d70d9ab955e887 Mon Sep 17 00:00:00 2001
From: Felipe Lema <felipelema@mortemale.org>
Date: Mon, 25 Jan 2016 16:22:44 -0300
Subject: [PATCH] Solves #81

---
 include/pybind11/pybind11.h | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/include/pybind11/pybind11.h b/include/pybind11/pybind11.h
index 166966a1c..d99a3ddb0 100644
--- a/include/pybind11/pybind11.h
+++ b/include/pybind11/pybind11.h
@@ -983,13 +983,30 @@ template <typename InputType, typename OutputType> void implicitly_convertible()
     ((detail::type_info *) it->second)->implicit_conversions.push_back(implicit_caster);
 }
 
-inline void init_threading() { PyEval_InitThreads(); }
+inline void init_threading() {
+#if defined(WITH_THREAD)
+  PyEval_InitThreads();
+#endif
+}
 
 class gil_scoped_acquire {
+#if defined(WITH_THREAD)
     PyGILState_STATE state;
+#endif
 public:
-    inline gil_scoped_acquire() { state = PyGILState_Ensure(); }
-    inline ~gil_scoped_acquire() { PyGILState_Release(state); }
+    inline gil_scoped_acquire() {
+#if defined(WITH_THREAD)
+      state = PyGILState_Ensure();
+#endif
+    } 
+    inline ~gil_scoped_acquire() {
+#if defined(WITH_THREAD)
+      PyGILState_Release(state); 
+#endif
+    }
+#if defined(WITH_THREAD)
+  PyEval_InitThreads();
+#endif
 };
 
 class gil_scoped_release {