Remove Uninitialized from HType.

BUG=
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/20711002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15925 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Fix V8_GNUC_PREREQ macro.

TBR=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/21049004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15926 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Fix d8 build error when V8_SHARED is unset on Linux.

TBR=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/21053002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15927 ce2b1a6d-e550-0410-aec6-3dcde31c8c00