Changes from 3.1.6 to 3.1.7
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1. Gawk now has support for z/OS (IBM S/390 architecture).
2. Gawk now handles multibyte strings better in [s]printf with field
widths and such.
3. Gawk now uses libsigsegv to print a message before core dumping. This
handles infinite recursion of an awk function a little better.
Use of the library can be disabled at configure time with the
--disable-libsigsegv option for unusual systems.
4. The handling of BINMODE is now somewhat more sane.
5. A getline from a directory is no longer fatal; instead it returns -1.
6. Per POSIX, special variable names (like FS) cannot be used as function
parameter names.
7. The new -O / --optimize option enables simple constant folding on
the parse tree during parsing. We hope that with time the number
of optimizations will increase.
8. Updated to the latest autotools: Autoconf 2.63, Automake 1.11,
Libtool 2.2.6a, and Gettext 0.17. Also latest Bison: 2.4.1.
9. Some improvement in testing for isinf / isnan in builtin.c.
10. Improved the handling of `a = a b c' to be more general.
11. Locale handling for %'d should now work on certain non-Unix /
non-Linux systems.
12. Lots of bugs fixed, see the ChangeLog for the details.
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