Added compile try_run() test to check mktime() for dates before 1970; setting symbol TIME_T_1970 for environments which can not take dates before 1970.
Added function ecl_util_make_date() which check symbol TIME_T_1970 - and shifts the years if neccessary.
Replacing util_make_date() -> ecl_util_make_date() in all of libecl
Changed to #define symbol TIME_T_64BIT_ACCEPT_PRE1970 + explicitly checking sizeof(time_t)
Merge pull request #203 from joakim-hove/time_t_1970_check

Time t 1970 check