Determine page size at runtime on posix platforms. Landing for kalmard. ...

Determine page size at runtime on posix platforms.  Landing for kalmard.  http://codereview.chromium.org/9023007/

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10337 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/platform-posix.cc

@@ -71,7 +71,8 @@ intptr_t OS::MaxVirtualMemory() {
 
 
 intptr_t OS::CommitPageSize() {
-  return 4096;
+  static intptr_t page_size = getpagesize();
+  return page_size;
 }