Adding Fredrik Lundh's _sre.c module and its header files.

NOTE: THIS IS VERY ROUGH ALPHA CODE!

Modules/sre.h

@@ -0,0 +1,38 @@
+/*
+ * Secret Labs' Regular Expression Engine
+ * $Id$
+ *
+ * simple regular expression matching engine
+ *
+ * Copyright (c) 1997-2000 by Secret Labs AB.  All rights reserved.
+ *
+ * See the _sre.c file for information on usage and redistribution.
+ */
+
+#ifndef SRE_INCLUDED
+#define SRE_INCLUDED
+
+#include "sre_constants.h"
+
+/* Python objects */
+
+typedef struct {
+    PyObject_HEAD
+    PyObject* code; /* link to the code string object */
+    PyObject* pattern; /* link to the pattern source (or None) */
+    int groups;
+    PyObject* groupindex;
+} PatternObject;
+
+#define PatternObject_GetCode(o) ((void*) PyString_AS_STRING((o)->code))
+
+typedef struct {
+    PyObject_HEAD
+    PyObject* string; /* link to the target string */
+    PatternObject* pattern; /* link to the regex (pattern) object */
+    int groups; /* number of groups (start/end marks) */
+    int mark[2];
+} MatchObject;
+
+#endif
+