Allow compiling PDFium without V8.

build/all.gyp

 # Copyright 2014 PDFium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'targets': [
     {
       'target_name': 'All',
       'type': 'none',
       'dependencies': [
-        '../pdfium.gyp:*',
+        '../pdfium.gyp:pdfium',
+        '../pdfium.gyp:pdfium_embeddertests',
+        '../pdfium.gyp:pdfium_unittests',
         '../samples/samples.gyp:*',
       ],
     }
   ]
 }