mksh R58

R58 contains a lot of fixes and improvements:

• hyphen-used-as-minus-sign (on jessie, not later, ‽‽‽)
• Fix system info gcc dump{machine,version} shell escaping level
• Document KSH_VERSIONNAME_VENDOR_EXT in Build.sh
• Be more explicit about the LTO bug exposed by check.t
• Add -x (file locks) and AIX-specific -r ulimits
• Handle Midipix as test environment and fix some warnings
• Fix some Build.sh issues as Mirtoconf is now used by MirCPIO and MagicPoint
• Improve CRLF to LF conversion
• Ensure ECHO mode is enabled at startup so read has local echo
• Let check.pl retain the PERLIO env variable
• Unbreak nounset-1 test on systems with drive letters
• Make ulimit-3 test work without |& (that is, incomplete ports, i.e. those with -DMKSH_NOPROSPECTOFWORK)
• Disable xxx-stat-1 test for now, fails when run as root
• Drop Build.sh flags -c combine, -c lto
• Exit 126 on execve(2) failure, not 1 (e.g. E2BIG)
• Behave set and export/readonly-on-read-only-variables when run with command and command dot
• dot.mkshrc: simplify; enhance (un)setting locale example
• Catch build errors earlier
• Add -fno-lto (if GCC is detected) to CFLAGS and LDFLAGS
• Limit HISTSIZE to 65535, as long pre-announced
• Unbreak testsuite selftest-tty-absent for lksh
• Begin work on support for neatcc (needs neatcc to evolve first)
• Fix possibly not enough aligned access in struct job
• Support going full setugid by running set -p once interactive
• Document another (arcane, almost nowhere needed) definition
• Improve code legibility and testsuite reliability and maintenance
• Speed up trivial += cases (LP#1855167)
• Some further code and memory optimisation and test coverage
• Document that += is always string append (LP#1857702)
• Fix “set -e appears active within eval but isn’t” and another bug related to using set ±e inside eval
• Handle parameter assignment in front of invocations of POSIX-style functions like ksh-style ones and external utilities; cf. Debian #935115
• Fix bad memory access for invalid syntax (LP#1857828, LP#1857826)
• Update MALLOC_OPTIONS-using testcase for newer OpenBSD
• Support lacc as compiler (just detecting, no change)
• Share __IDSTRING with jupp
• Update string comparison/pattern documentation
• Document vi command line editing mode state better
• Add FAQ2HTML.sh to convert mksh.faq to local valid XHTML+CSS
• Correct backslash expansion documentation; caveat re. 16-bit UCS
• Fix extra empty field on IFS-NWS trim expansion
• Improve code performance, quality, robustness and correctness
• Allow ${x:n} where n is an identifier
• Permit + in alias names, but not leading
• Fix here strings for $@ (LP#1857195)
• Add vi mode PgDn, similar to PgUp doing history search
• Build.sh fixup unreliable test -n/-z
• Correct documentation of vi mode @c
• Update to UCD 13.0.0
• Use nanoseconds in test -nt / -ot (LP#1855325)