bug#46581: Test failures on cygwin

[Soren]

I ran `make check' after building sed on cygwin (using the cygport tool to
run all the usual commands). A couple of tests failed:

============================================================================
Testsuite summary for GNU sed 4.4
============================================================================
# TOTAL: 108
# PASS:  104
# SKIP:  2
# XFAIL: 0
# FAIL:  2
# XPASS: 0
# ERROR: 0
============================================================================
See ./test-suite.log
Please report to bug-sed@gnu.org
============================================================================
make[4]: *** [Makefile:3142: test-suite.log] Error 1
make[4]: Leaving directory '/usr/src/sed-4.4-1.src/sed-4.4-1.x86_64/build'
make[3]: *** [Makefile:3250: check-TESTS] Error 2
make[3]: Leaving directory '/usr/src/sed-4.4-1.src/sed-4.4-1.x86_64/build'
make[2]: *** [Makefile:4090: check-am] Error 2
make[2]: Leaving directory '/usr/src/sed-4.4-1.src/sed-4.4-1.x86_64/build'
make[1]: *** [Makefile:3027: check-recursive] Error 1
make[1]: Leaving directory '/usr/src/sed-4.4-1.src/sed-4.4-1.x86_64/build'
make: *** [Makefile:4092: check] Error 2

The lines containing the failure output:


make[4]: Entering directory '/usr/src/sed-4.4-1.src/sed-4.4-1.x86_64/build'
FAIL: testsuite/get-mb-cur-max.exe
FAIL: testsuite/test-mbrtowc.exe


This may have already been reported upstream, I know.

     Cheers,
       Soren A.