[bug #4296] PUTD() macro can't hack 10 digit values

Once the number exceeded 1000000000, the conversion would fail.  An execution of
 dp -format "%(clock{text})" "Tue, 01 Jul 2003 21:38:05 +0700" would erroneously print
749660476, instead of 1057070285.

The macros PUTD() and PUTDF() have been replaced by snprintf() calls;  These macros
should never have been written in the first place, when system functions exist to do the
work.