checksrc.pl: add -i and -m options

To sync it with changes made for the libssh2 project.
Also cleanup some whitespace.

lib/checksrc.pl

@@ -6,7 +6,7 @@
 #                            | (__| |_| |  _ <| |___
 #                             \___|\___/|_| \_\_____|
 #
-# Copyright (C) 2011 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
+# Copyright (C) 2011 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
 #
 # This software is licensed as described in the file COPYING, which
 # you should have received as part of this distribution. The terms
@@ -142,6 +142,16 @@ while(1) {
         $file = shift @ARGV;
         next;
     }
+    elsif($file =~ /-i([1-9])/) {
+        $indent = $1 + 0;
+        $file = shift @ARGV;
+        next;
+    }
+    elsif($file =~ /-m([0-9]+)/) {
+        $max_column = $1 + 0;
+        $file = shift @ARGV;
+        next;
+    }
     elsif($file =~ /^(-h|--help)/) {
         undef $file;
         last;
@@ -156,6 +166,8 @@ if(!$file) {
     print "  -D[DIR]   Directory to prepend file names\n";
     print "  -h        Show help output\n";
     print "  -W[file]  Whitelist the given file - ignore all its flaws\n";
+    print "  -i<n>     Indent spaces. Default: 2\n";
+    print "  -m<n>     Maximum line length. Default: 79\n";
     print "\nDetects and warns for these problems:\n";
     for(sort keys %warnings) {
         printf (" %-18s: %s\n", $_, $warnings{$_});