Changelist http://codereview.chromium.org/20177 caused linking of mksnapshot to fail as link libraries where not specified. Updated build to link mksnapshot with pthread on Linux and Mac OS and with winmm on Windows.
Review URL: http://codereview.chromium.org/21171

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1241 ce2b1a6d-e550-0410-aec6-3dcde31c8c00