+AC_ARG_ENABLE(strptime-sanity-checks,
+[ --enable-strptime-sanity-checks Only trust strptime() results if an additional strftime()/strptime()
+ conversion doesn't change the result. Can be useful if strptime() is
+ known or suspected to be broken.],
+[if test $enableval = yes; then
+ AC_DEFINE(FEATURE_STRPTIME_SANITY_CHECKS)
+fi])
+