Log Message:
mawk: update to 20200120

20200120
	+ resync with my-autoconf.
	+ fix typos found with codespell.
	+ when reading input in interactive mode, provide for extending the
	  buffer size for very long lines (Original-Mawk #59).

20200106
	+ correct line-number shown in too-many-arguments error message for
	  the case where the function is a forward reference (report by
	  "mukti").
	+ fix install for manpage when configure --srcdir option is used
	  (report by Rajeev V Pillai).
	+ use both CFLAGS/LDFLAGS when linking in makefile (report by
	  Rajeev V Pillai).
	+ fix clang-9 warning in bi_funct.c (report by Rajeev V Pillai).
	+ minor improvement to gcc warning options, from vile

20191231
	+ updated configure macros
	+ update config.guess and config.sub

20190203
	+ improve manpage formatting, e.g., for man2html
	+ improve debug-traces

20190129
	+ eliminate non-portable tdestroy() from zmalloc no-leaks code.
	+ updated configure macros
	+ update config.guess and config.sub

20181114
	+ revert a change for memory-leaks which made the forced-exit via a
	  user function inconsistent with earlier versions (report by Sihera
	  Andre).
	+ amend a change for memory-leaks to avoid a double-free (Original-Mawk
	  #56).