Add v8_os_page_size flag for cross compilation

src/heap/spaces.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_SPACES_H_
 #define V8_HEAP_SPACES_H_
 
 #include <list>
 #include <memory>
 #include <unordered_set>
@@ skipping 1072 matching lines @@
   static const int kSize = Page::kPageSize / kRegionSize;
 
   STATIC_ASSERT(Page::kPageSize % kRegionSize == 0);
 
   Address starts_[kSize];
 };
 
 
 // ----------------------------------------------------------------------------
 // A space acquires chunks of memory from the operating system. The memory
-// allocator allocated and deallocates pages for the paged heap spaces and large
+// allocator allocates and deallocates pages for the paged heap spaces and large
 // pages for large object space.
 class MemoryAllocator {
  public:
   // Unmapper takes care of concurrently unmapping and uncommitting memory
   // chunks.
   class Unmapper {
    public:
     class UnmapFreeMemoryTask;
 
     explicit Unmapper(MemoryAllocator* allocator)
@@ skipping 98 matching lines @@
   static size_t CodePageAreaSize() {
     return CodePageAreaEndOffset() - CodePageAreaStartOffset();
   }
 
   static size_t PageAreaSize(AllocationSpace space) {
     DCHECK_NE(LO_SPACE, space);
     return (space == CODE_SPACE) ? CodePageAreaSize()
                                  : Page::kAllocatableMemory;
   }
 
+  static intptr_t GetCommitPageSize();
+
   explicit MemoryAllocator(Isolate* isolate);
 
   // Initializes its internal bookkeeping structures.
   // Max capacity of the total space and executable memory limit.
   bool SetUp(size_t max_capacity, size_t capacity_executable,
              size_t code_range_size);
 
   void TearDown();
 
   // Allocates a Page from the allocator. AllocationMode is used to indicate
@@ skipping 1685 matching lines @@
   PageIterator old_iterator_;
   PageIterator code_iterator_;
   PageIterator map_iterator_;
   LargePageIterator lo_iterator_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_SPACES_H_