usual.m4: fix localtime_r typo
usual.m4: fix localtime_r typo

markokr/libusual,rabbitt/libusual,rabbitt/libusual,mgjv/libusual,ifduyue/libusual,markokr/libusual,ifduyue/libusual,markokr/libusual,rabbitt/libusual,ifduyue/libusual,mgjv/libusual,markokr/libusual,mgjv/libusual,rabbitt/libusual,mgjv/libusual,ifduyue/libusual