#27364: fix "incorrect" uses of escape character in the stdlib.

And most of the tools.

Patch by Emanual Barry, reviewed by me, Serhiy Storchaka, and
Martin Panter.

Lib/http/client.py

@@ -1,4 +1,4 @@
-"""HTTP/1.1 client library
+r"""HTTP/1.1 client library
 
 <intro stuff goes here>
 <other stuff, too>

Lib/http/cookiejar.py

@@ -200,7 +200,7 @@ def _str2time(day, mon, yr, hr, min, sec, tz):
 
 STRICT_DATE_RE = re.compile(
     r"^[SMTWF][a-z][a-z], (\d\d) ([JFMASOND][a-z][a-z]) "
-    "(\d\d\d\d) (\d\d):(\d\d):(\d\d) GMT$", re.ASCII)
+    r"(\d\d\d\d) (\d\d):(\d\d):(\d\d) GMT$", re.ASCII)
 WEEKDAY_RE = re.compile(
     r"^(?:Sun|Mon|Tue|Wed|Thu|Fri|Sat)[a-z]*,?\s*", re.I | re.ASCII)
 LOOSE_HTTP_DATE_RE = re.compile(
@@ -277,7 +277,7 @@ def http2time(text):
     return _str2time(day, mon, yr, hr, min, sec, tz)
 
 ISO_DATE_RE = re.compile(
-    """^
+    r"""^
     (\d{4})              # year
        [-\/]?
     (\d\d?)              # numerical month
@@ -411,7 +411,7 @@ def split_header_words(header_values):
                 pairs = []
             else:
                 # skip junk
-                non_junk, nr_junk_chars = re.subn("^[=\s;]*", "", text)
+                non_junk, nr_junk_chars = re.subn(r"^[=\s;]*", "", text)
                 assert nr_junk_chars > 0, (
                     "split_header_words bug: '%s', '%s', %s" %
                     (orig_text, text, pairs))

Lib/http/cookies.py

@@ -456,7 +456,7 @@ class Morsel(dict):
 #
 
 _LegalKeyChars  = r"\w\d!#%&'~_`><@,:/\$\*\+\-\.\^\|\)\(\?\}\{\="
-_LegalValueChars = _LegalKeyChars + '\[\]'
+_LegalValueChars = _LegalKeyChars + r'\[\]'
 _CookiePattern = re.compile(r"""
     (?x)                           # This is a verbose pattern
     \s*                            # Optional whitespace at start of cookie