https://github.com/boostorg/python/commit/3e405b6fd5db5615bbef241763de070118222ca7

--- libs/python/src/exec.cpp
+++ libs/python/src/exec.cpp
@@ -86,9 +86,12 @@
   char *f = python::extract<char *>(filename);
 
   // Let python open the file to avoid potential binary incompatibilities.
-#if PY_VERSION_HEX >= 0x03000000
-  // See http://www.codeproject.com/Articles/820116/Embedding-Python-program-in-a-C-Cplusplus-code
+#if PY_VERSION_HEX >= 0x03040000
   FILE *fs = _Py_fopen(f, "r");
+#elif PY_VERSION_HEX >= 0x03000000
+  PyObject *fo = Py_BuildValue("s", f);
+  FILE *fs = _Py_fopen(fo, "r");
+  Py_DECREF(fo);
 #else
   PyObject *pyfile = PyFile_FromString(f, const_cast<char*>("r"));
   if (!pyfile) throw std::invalid_argument(std::string(f) + " : no such file");