Fix bug reported by atkins@gweep.net; re.compile(r"[\100-\410]")
dumps core. Solution: fix check_escape() to match its comment and
use only the low 8 bits of the octal number.
diff --git a/Modules/pypcre.c b/Modules/pypcre.c
index 468751d..afff59c 100644
--- a/Modules/pypcre.c
+++ b/Modules/pypcre.c
@@ -1064,7 +1064,7 @@
c -= '0';
while(i++ < 2 && (pcre_ctypes[ptr[1]] & ctype_digit) != 0 &&
ptr[1] != '8' && ptr[1] != '9')
- c = c * 8 + *(++ptr) - '0';
+ c = (c * 8 + *(++ptr) - '0') & 255;
break;
/* Special escapes not starting with a digit are straightforward */