diff --git a/src/if_python3.c b/src/if_python3.c
index 59ef88f..5400dc6 100644
--- a/src/if_python3.c
+++ b/src/if_python3.c
@@ -42,19 +42,21 @@
 # undef _DEBUG
 #endif
 
-#ifdef HAVE_STDARG_H
-# undef HAVE_STDARG_H   /* Python's config.h defines it as well. */
-#endif
-
 #define PY_SSIZE_T_CLEAN
 
 #ifdef F_BLANK
 # undef F_BLANK
 #endif
 
+#ifdef HAVE_STDARG_H
+# undef HAVE_STDARG_H   /* Python's config.h defines it as well. */
+#endif
 #ifdef _POSIX_C_SOURCE  /* defined in feature.h */
 # undef _POSIX_C_SOURCE
 #endif
+#ifdef _XOPEN_SOURCE
+# undef _XOPEN_SOURCE	/* pyconfig.h defines it as well. */
+#endif
 
 #include <Python.h>
 #if defined(MACOS) && !defined(MACOS_X_UNIX)
@@ -436,7 +438,7 @@
 static void PythonIO_Flush(void);
 static int PythonIO_Init(void);
 static void PythonIO_Fini(void);
-PyMODINIT_FUNC Py3Init_vim(void);
+static PyMODINIT_FUNC Py3Init_vim(void);
 
 /* Utility functions for the vim/python interface
  * ----------------------------------------------
@@ -630,7 +632,7 @@
 }
 
 /*
- * ":python"
+ * ":python3"
  */
 void ex_python3(exarg_T *eap)
 {
@@ -650,7 +652,7 @@
 #define BUFFER_SIZE 2048
 
 /*
- * ":pyfile"
+ * ":py3file"
  */
     void
 ex_py3file(exarg_T *eap)
@@ -2220,7 +2222,7 @@
 
 static struct PyModuleDef vimmodule;
 
-PyMODINIT_FUNC Py3Init_vim(void)
+static PyMODINIT_FUNC Py3Init_vim(void)
 {
     PyObject *mod;
     /* The special value is removed from sys.path in Python3_Init(). */