Upgrade to mksh R59b.

R59b is a must-have bugfix upgrade for R59 (not R58):

[tg] Handle other tmux $TERM types, pointed out by multi via IRC
[tg] Fix typo in FAQ
[tg] y='a\*b'; [[ $x = $y ]] regression (Martijn Dekker) fix
[l0kod] Defuse CLIP OS O_MAYEXEC support (cf. LWN)
[tg] Make set +o output a command to restore the currently set and
(new!) cleared options, keep a reset state per session (experimental)
[tg] Correct documentation and code regarding to argv[0] parsing: first
‘-’ for login shells, then ‘r’ case-insensitively for restricted shell,
then “sh”*, again case-insensitively, for BINSH_* modes; add tests
[tg] On OS/2, allow case-insensitive name for direct builtin call
[tg] Always skip startup files if direct builtin call
[tg] Avoid some sometimes-redundant startup codepaths

Test: treehugger
Change-Id: I7b0a1d37b4d3fdf1f78569458769e89dca755fcb
14 files changed