To make these calls threadsafe. localtime_r is provided by gnulib if
necessary, and for ctime_r we can just use it because it is in a linux-
specific file.
gdb/ChangeLog:
2019-11-15 Christian Biesinger <cbiesinger@google.com>
* maint.c (scoped_command_stats::print_time): Use localtime_r
instead of localtime (provided through gnulib if necessary).
* nat/linux-osdata.c (time_from_time_t): Use ctime_r instead
of ctime.
Change-Id: I329bbdc39d5b576f51859ba00f1617e024c30cbd
