mktime() when timezone offest is supplied.

mktime() when timezone offest is supplied.

Original patch by Jim Jewett; see issue 14684.

These functions were originally added to support LZMA compression in the zipfile
module, and are not of interest for the majority of users.

They can be made public in 3.4 if there is user interest, but in the meanwhile,
I've opted to present a smaller, simpler API for the module's initial release.

Loosely based on the work by Hirokazu Yamamoto.

Loosely based on the work by Hirokazu Yamamoto.

    1. on OS X, there is no separate /usr/lib/libcursesw nor libpanelw
    2. _XOPEN_SOURCE_EXTENDED must be enabled for _curses build

Original patch by Sam Rushing.

  1) _mpd_qdivmod() uses the context precision only in two places, and
     the new code should be exactly equivalent to the previous code.

  2) Remove misleading comment.

  3) The quotient *is* an integer with exponent 0, so calling mpd_qtrunc()
     is pointless.

  4) Replace two instances of identical code by a single one.

  5) Use _mpd_cmp_abs() instead of mpd_cmp_total_mag(): the operands
     are not special.

  6) Don't clear MPD_Rounded in the status (with the current code it should
     not be set within the function).

Clarified comment on disabled code to reference issue15093.

Add relevant tests for GzipFile, and also for BZ2File and LZMAFile.