make gc branch compile on Win32.

src/spaces.h

Index: src/spaces.h
diff --git a/src/spaces.h b/src/spaces.h
index b16d26024ca6af19efa5af9feb74eba10089b872..24aaaa03045f8f7ab0c71f4abade04907af3de9b 100644
--- a/src/spaces.h
+++ b/src/spaces.h
@@ -303,7 +303,7 @@ class MemoryChunk {
 
   Address body() { return address() + kBodyOffset; }
 
-  int body_size() { return size() - kBodyOffset; }
+  int body_size() { return static_cast<int>(size() - kBodyOffset); }
 
   enum MemoryChunkFlags {
     IS_EXECUTABLE,
@@ -311,18 +311,19 @@ class MemoryChunk {
   };
 
   void SetFlag(int flag) {
-    flags_ |= 1 << flag;
+    flags_ |= static_cast<uintptr_t>(1) << flag;
   }
 
   void ClearFlag(int flag) {
-    flags_ &= ~(1 << flag);
+    flags_ &= ~(static_cast<uintptr_t>(1) << flag);
   }
 
   bool IsFlagSet(int flag) {
-    return (flags_ & (1 << flag)) != 0;
+    return (flags_ & (static_cast<uintptr_t>(1) << flag)) != 0;
   }
 
-  static const intptr_t kAlignment = (1 << kPageSizeBits);
+  static const intptr_t kAlignment =
+      (static_cast<uintptr_t>(1) << kPageSizeBits);
 
   static const intptr_t kAlignmentMask = kAlignment - 1;