Add patch to fix build with Python 3.7

boost-1.66.0-python37.patch

@@ -0,0 +1,39 @@
+From 660487c43fde76f3e64f1cb2e644500da92fe582 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Bernhard=20Rosenkr=C3=A4nzer?= <bero@lindev.ch>
+Date: Fri, 9 Feb 2018 18:20:30 +0100
+Subject: [PATCH] Fix build with Python 3.7
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Python 3.7 changes the return type of _PyUnicode_AsString()
+from void* to const char* -- causing the build of boost-python
+to fail.
+
+Signed-off-by: Bernhard Rosenkränzer <bero@lindev.ch>
+---
+ src/converter/builtin_converters.cpp | 7 ++++++-
+ 1 file changed, 6 insertions(+), 1 deletion(-)
+
+diff --git a/src/converter/builtin_converters.cpp b/src/converter/builtin_converters.cpp
+index 1c28af7fc..ee2d5b479 100644
+--- a/libs/python/src/converter/builtin_converters.cpp
++++ b/libs/python/src/converter/builtin_converters.cpp
+@@ -45,11 +45,16 @@ namespace
+   {
+       return PyString_Check(obj) ? PyString_AsString(obj) : 0;
+   }
+-#else
++#elif PY_VERSION_HEX < 0x03070000
+   void* convert_to_cstring(PyObject* obj)
+   {
+       return PyUnicode_Check(obj) ? _PyUnicode_AsString(obj) : 0;
+   }
++#else
++  void* convert_to_cstring(PyObject* obj)
++  {
++      return PyUnicode_Check(obj) ? const_cast<void*>(reinterpret_cast<const void*>(_PyUnicode_AsString(obj))) : 0;
++  }
+ #endif
+ 
+   // Given a target type and a SlotPolicy describing how to perform a