libbb: code shrink parse_datestr

The default build uses strptime() in parse_datestr() to support the
'month_name d HH:MM:SS YYYY' format of GNU date.  If we've linked
with strptime() there's an advantage is using it for other formats
too.

There's no change to the non-default, non-DESKTOP build.

function                                             old     new   delta
fmt_str                                                -     106    +106
.rodata                                            99216   99145     -71
parse_datestr                                        948     624    -324
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/2 up/down: 106/-395)         Total: -289 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
1 file changed