checkpatch: allow long lines containing URL

Allow lines with URL to exceed the 80 char limit for improved interaction
in adaption to ongoing but undocumented practice.

  $ git grep -E '://\S{77}.*' -- '*.[ch]'

As per RFC3986 [1], the URL format allows for alphanum, +, - and .
characters in the scheme before the separator :// as long as it starts
with a letter (e.g.  https, git, f.-+).

Recognition of URIs without more context information is prone to false
positives and thus currently left out of the heuristics.

$rawline is used in the check as comments are removed from $line.

[1] https://tools.ietf.org/html/rfc3986#section-3.1

Link: http://lkml.kernel.org/r/1511355432.12667.15.camel@elementarea.net
Signed-off-by: Andreas Brauchli <andreas.brauchli@sensirion.com>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/checkpatch.pl

@@ -2875,6 +2875,7 @@ sub process {
 #	logging functions like pr_info that end in a string
 #	lines with a single string
 #	#defines that are a single string
+#	lines with an RFC3986 like URL
 #
 # There are 3 different line length message types:
 # LONG_LINE_COMMENT	a comment starts before but extends beyond $max_line_length
@@ -2906,6 +2907,10 @@ sub process {
 				 $line =~ /^\+\s*(?:\w+)?\s*DEFINE_PER_CPU/) {
 				$msg_type = "";
 
+			# URL ($rawline is used in case the URL is in a comment)
+			} elsif ($rawline =~ /^\+.*\b[a-z][\w\.\+\-]*:\/\/\S+/i) {
+				$msg_type = "";
+
 			# Otherwise set the alternate message types
 
 			# a comment starts before $max_line_length