basic autoheader/autom4te not working for me, mixed ascii/ebcdic during m4

[covener]

Will try to describe my sandbox and result.

My bash is rocket 4.3.48 (this orgs bash5 noc hange) with this ascii env:

export _BPXK_AUTOCVT=ON
export _CEE_RUNOPTS="FILETAG(AUTOCVT,AUTOTAG) POSIX(ON)"

#export _TAG_REDIR_IN=txt
#export _TAG_REDIR_OUT=txt
#export _TAG_REDIR_ERR=txt

I end my ~/.bashrc with the following to use some contemporary tools from this org:

for DIR in curl-7.83.1.20221004_225315.zos m4-1.4.19.20221024_100531.zos autoconf-2.71.20221007_003454.zos; do
  cd $DIR
  source .env
  cd -
done

And a dummy configure.in to test autoconf outside of my full httpd sandbox

AC_PREREQ(2.59)
AC_INIT(export_vars.sh.in)
AC_CONFIG_HEADER(dummy.h)

autoheader always produces an error:

$ autoheader
autoheader: warning: autoconf input should be named 'configure.ac', not 'configure.in'
m4:/tmp/am4tJP4czz/traces.m4:126: ERROR: end of file in comment
m4:/tmp/am4tJP4czz/traces.m4:128: ERROR: end of file in comment
m4:/tmp/am4tJP4czz/traces.m4:130: ERROR: end of file in comment
autoheader: error: error: AC_CONFIG_HEADERS not found in configure.in

with -v

autom4te: formatting traces for '/tmp/am4tmnNLwA/warnings': _m4_warn
m4:/tmp/am4tmnNLwA/traces.m4:128: ERROR: end of file in comment

Putting a sleep at the bottom of handle_traces in autom4te shows:

$ ls -T /tmp/am4tmnNLwA/traces.m4
t IBM-1047    T=on  /tmp/am4tmnNLwA/traces.m4

Which has multiple cases of ascii content after leading stanzas of ebcdic. I've sftp'ed it off the host and gzip'ed it to allow it to be attached:

traces.m4.gz

[covener]

Works with perlport but not rocketperl 5.24