Change stack alignment on linux to 16 bytes to keep gcc 4.4 happy. 
This fixes the mksnapshot segfault without requiring -fno-tree-vectorize
which just avoided the problem by not generating code with movdqa.


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2107 ce2b1a6d-e550-0410-aec6-3dcde31c8c00