Basic underpinnings of the gyp equivalent of the Linux SHARED=1 build:...

third_party/zlib/zlib.gyp

 # Copyright (c) 2009 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'includes': [
     '../../build/common.gypi',
   ],
   'targets': [
     {
       'target_name': 'zlib',
-      'type': 'static_library',
+      'type': '<(library)',
       'msvs_guid': '8423AF0D-4B88-4EBF-94E1-E4D00D00E21C',
       'sources': [
         'contrib/minizip/ioapi.c',
         'contrib/minizip/ioapi.h',
         'contrib/minizip/iowin32.c',
         'contrib/minizip/iowin32.h',
         'contrib/minizip/unzip.c',
         'contrib/minizip/unzip.h',
         'adler32.c',
         'compress.c',
@@ skipping 33 matching lines @@
         ['OS!="win"', {
           'product_name': 'z',
           'sources!': [
             'contrib/minizip/iowin32.c'
           ],
         }],
       ],
     },
   ],
 }