Don't start a state restoration if it is not available.
Fortuitly discovered that $SECONDS is inherited from shell to sub-shells. Good!
1 Index: libc/misc/time/time.c
2 ===================================================================
3 --- a/libc/misc/time/time.c (revision 17534)
4 +++ b/libc/misc/time/time.c (revision 17647)
8 #if defined (L_tzset) || defined (L_localtime_r) || defined(L_strftime) || \
9 - defined(L__time_mktime) || defined(L__time_mktime_tzi)
10 + defined(L__time_mktime) || defined(L__time_mktime_tzi) || \
11 + ((defined(L_strftime) || defined(L_strftime_l)) && \
12 + defined(__UCLIBC_HAS_XLOCALE__))
14 void _time_tzset (int);