This is the version used for Windows already and contains the fix for
building against spidermonkey on all Linux distributions.
Backport patch to fix running on *BSD. Also make clang default on *BSD
as a toolset will always added to generated makefiles in beta3, so it
won't magically do what we expect when not adding --cc explicitly.
Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>