Remove TIME_WITH_SYS_TIME
The macro TIME_WITH_SYS_TIME is no longer defined due to the removal of the AC_HEADER_TIME option in configure.ac.
AC_HEADER_TIME was removed to make configure.ac compatible with autoconf 2.70 (and newer).
This MR removes TIME_WITH_SYS_TIME from GMP-ECM source files.
Edited by David Cleaver