Adding Fredrik Lundh's _sre.c module and its header files.
NOTE: THIS IS VERY ROUGH ALPHA CODE!
diff --git a/Modules/sre_constants.h b/Modules/sre_constants.h
new file mode 100644
index 0000000..6b940d3
--- /dev/null
+++ b/Modules/sre_constants.h
@@ -0,0 +1,27 @@
+/* generated by sre_constants.py */
+#define SRE_OP_FAILURE 0
+#define SRE_OP_SUCCESS 1
+#define SRE_OP_ANY 2
+#define SRE_OP_ASSERT 3
+#define SRE_OP_AT 4
+#define SRE_OP_BRANCH 5
+#define SRE_OP_CALL 6
+#define SRE_OP_CATEGORY 7
+#define SRE_OP_GROUP 8
+#define SRE_OP_GROUP_IGNORE 9
+#define SRE_OP_IN 10
+#define SRE_OP_IN_IGNORE 11
+#define SRE_OP_JUMP 12
+#define SRE_OP_LITERAL 13
+#define SRE_OP_LITERAL_IGNORE 14
+#define SRE_OP_MARK 15
+#define SRE_OP_MAX_REPEAT 16
+#define SRE_OP_MAX_UNTIL 17
+#define SRE_OP_MAX_REPEAT_ONE 18
+#define SRE_OP_MIN_REPEAT 19
+#define SRE_OP_MIN_UNTIL 20
+#define SRE_OP_NOT_LITERAL 21
+#define SRE_OP_NOT_LITERAL_IGNORE 22
+#define SRE_OP_NEGATE 23
+#define SRE_OP_RANGE 24
+#define SRE_OP_REPEAT 25