Expose Subversion revision number (calculated via "svnversion .") to Python.
Add C API function Py_GetBuildNumber(), add it to the interactive prompt
banner (i.e. Py_GetBuildInfo()), and add it as the sys.build_number
attribute.  The build number is a string instead of an int because it may
contain a trailing 'M' if there are local modifications.
diff --git a/Modules/getbuildinfo.c b/Modules/getbuildinfo.c
index b541bb6..8b1ca22 100644
--- a/Modules/getbuildinfo.c
+++ b/Modules/getbuildinfo.c
@@ -21,7 +21,7 @@
 #endif
 
 #ifndef BUILD
-#define BUILD 0
+#define BUILD "0"
 #endif
 
 const char *
@@ -29,6 +29,12 @@
 {
 	static char buildinfo[50];
 	PyOS_snprintf(buildinfo, sizeof(buildinfo),
-		      "#%d, %.20s, %.9s", BUILD, DATE, TIME);
+		      "%s, %.20s, %.9s", BUILD, DATE, TIME);
 	return buildinfo;
 }
+
+const char *
+Py_GetBuildNumber(void)
+{
+	return BUILD;
+}