m4 test-c-stack2.sh test failing on sparc64-linux-gnu

[John Paul Adrian Glaubitz]

Hello!

m4 has been failing to build from source on Debian sparc64 for a while now
since the test test-c-stack2.sh fails on this architecture with:

FAIL: test-c-stack2.sh
======================

cannot tell stack overflow from crash, in spite of libsigsegv
FAIL test-c-stack2.sh (exit status: 1)

This is for version 1.4.18, the full build log can be found in [1].

The gcc compile farm provides two Debian sparc64 and two Solaris SPARC
machines which can be used for debugging purposes [2].

Thanks,
Adrian

> [1] 
> https://buildd.debian.org/status/fetch.php?pkg=m4&arch=sparc64&ver=1.4.18-4&stamp=1605390081&raw=0
> [2] https://gcc.gnu.org/wiki/CompileFarm

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz@debian.org
`. `'   Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de
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