Bug#760870: Patch to fix this issue

[ppm]

Hi,

The patch attached with this email seems to solve this issue.

I have applied it the ack-grep source code in sid and ran `make test'
without any error.

Should we add one test case in ack-grep source to specifically test this
use case?

Thanks,
Partha

--- ack.orig	2014-09-04 03:48:46.000000000 +0000
+++ ack	2014-09-12 08:24:46.744780094 +0000
@@ -331,7 +331,7 @@
         $str = "(?i)$str";
     }
 
-    my $re = eval { qr/$str/ };
+    my $re = eval { qr/$str/m };
     if ( !$re ) {
         die "Invalid regex '$str':\n  $@";
     }