Bison 3.5.93 on AIX 7.2

On AIX 7.2, when building with gcc in 32-bit mode, there are three problems:

1) FAIL: examples/c/reccalc/reccalc.test
As reported in
<https://lists.gnu.org/archive/html/bug-bison/2020-05/msg00047.html> .


2) "gmake -k check" goes past 1) and starts to execute the ca. 600 individual
tests, but it aborts like this:

276: Several parsers                                 ok
../tests/testsuite[25]: syntax error at line 3 : `)' unexpected
Makefile:11650: recipe for target 'check-local' failed
gmake[3]: *** [check-local] Error 2

The workaround is to change, in the Makefile,
  SHELL = /bin/sh
to
  SHELL = /bin/bash

Then "gmake -k check" executes the full test suite.

I added a 'set -x' at the top of tests/testsuite, ran "gmake -k check" with
and without the change, and compared the two outputs. But it gives no clue
why /bin/sh chokes in the middle. 


3) There are three test failures:
137: Tabulations and multibyte characters            FAILED (diagnostics.at:280)
527: GNU AWK 3.1.0 Grammar: IELR(1)                  FAILED (existing.at:801)
533: GNU pic (Groff 1.18.1) Grammar: IELR(1)         FAILED (existing.at:3266)

Detailed configuration:

CC="gcc"; CXX="g++"; export CC CXX
unset AR NM

Detailed test results: attached.

The first test failure is like on Cygwin: because wchar_t is only 16 bits
wide, in 32-bit AIX.

The two other test failures are like on AIX 7.1, see
<https://lists.gnu.org/archive/html/bug-bison/2020-05/msg00049.html>.