build: shorten configurate script print on stdout

Reduces the previously pretty-printed configuration dictionary to a
single line wrapped at 78 characters. This makes warning messages which
appear before this print more visible to the user.

PR-URL: #483
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Saúl Ibarra Corretgé <saghul@gmail.com>

configure

@@ -8,6 +8,7 @@ import subprocess
 import sys
 import shutil
 import string
+import textwrap
 
 CC = os.environ.get('CC', 'cc')
 CXX = os.environ.get('CXX', 'c++')
@@ -960,7 +961,7 @@ output = {
   'variables': variables,
   'target_defaults': output
 }
-pprint.pprint(output, indent=2)
+print textwrap.fill(str(output), 78)
 
 write('config.gypi', do_not_edit +
       pprint.pformat(output, indent=2) + '\n')