* ext/date/date_core.c (DateTimeData): should not use bare 'long long'
and 'long double', which are not defined by C89.
* ext/date/date_core.c (dt_lite_plus): get rid of overflow at casting
down double to integer.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@31039 b2dd03c8-39d4-4d8f-98ff-823fe69b080e