config.status[12]: export: SHELL##: is not an identifier

Today I am testing GraphicsMagick builds in a Illumos/OmniOS (decedent 
of OpenSolaris) environment which has been stable for quite some time, 
and am shocked by a problem with config.status.

This happens:

  /bin/sh ./config.status
./config.status[12]: export: SHELL##: is not an identifier

and when I go look in the generated config.status I see this:

SHELL=${CONFIG_SHELL-/bin/sh}
export SHELL## -------------------- ##
## M4sh Initialization. ##
## -------------------- ##

Somehow an expected newline is missing and the shell is not handling 
it.  The bang line at the top of the script is "#! /bin/sh".

If I use an editor to correct this issue (by adding a newline), then all 
works fine unless config.status is generated again (for example, if I 
execute "./config.status --recheck).

The tool versions used are autoconf 2.71, automake 1.16.5, libtool 
2.4.7, GNU m4 1.4.18, GNU sed 4.7, and bash 5.0.9.

Although it is not responsible for the issue (issue was pre-existing), I 
installed automake today and its test suite showed only 3 test failures.

What might have introduced this problem, and how can I fix it?

Bob

-- 
Bob Friesenhahn
[email protected], http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
Public Key,     http://www.simplesystems.org/users/bfriesen/public-key.txt