MacOSX: Configure curl for MacOSX

Create a new MacOSX configuration for curl:
- Add a curl_config.h created on MacOSX
- Add a find_curl_ca_bundle.sh that searches default folder from Homebrew and MacPorts for a ca bundle.
  To find the files either install OpenSSL from Homebrew or MacPorts, or Curl from MacPorts.

packager/third_party/curl/config/mac/find_curl_ca_bundle.sh

@@ -0,0 +1,23 @@
+#!/bin/bash -e
+
+# Copyright 2015 Google Inc. All rights reserved.
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+# Scan ca bundle in its common appearing locations.
+paths=('/opt/local/etc/openssl/cert.pem'  # macports
+       '/opt/local/share/curl/curl-ca-bundle.crt' # macports
+       '/usr/local/etc/openssl/cert.pem'  # homebrew
+)
+
+for path in "${paths[@]}"; do
+  if test -f "$path"; then
+    echo "$path"
+    exit 0
+  fi
+done
+
+echo 'Failed to locate SSL CA cert.'
+exit 1

packager/third_party/curl/curl.gyp

@@ -43,6 +43,20 @@
             ],
           },
         }],
+        ['OS == "mac"', {
+          'sources': [
+            'config/mac/curl_config.h',
+          ],
+          'direct_dependent_settings': {
+            'defines': [
+              'HAVE_CONFIG_H',
+              'CURL_CA_BUNDLE="<!(config/mac/find_curl_ca_bundle.sh)"',
+            ],
+            'include_dirs': [
+              'config/mac',
+            ],
+          },
+        }],
         ['OS == "win"', {
           'direct_dependent_settings': {
             'link_settings': {