I'm really not very good at this configure magic :-(
I thought I'd start with the warning messages for old versions of xforms.
The relevant bit of xforms.m4 is:
XFORMS_VERSION=$lyx_cv_xfversion
case "$lyx_cv_xfversion" in
"(unknown)"|0.8[1-8]*|0.89[01234])
LYX_ERROR(dnl
Version $lyx_cv_xfversion of xforms is not compatible with LyX.
This version of LyX works best with version 1.0 (recommended) and later.)
;;
0.89*|0.9999*)
LYX_WARNING(dnl
LyX should work ok with version $lyx_cv_xfversion of xforms[,] but
it contains many bugs that have been squashed in version 1.0.
You should consider upgrading.) ;;
1.0*) ;;
fi
])
Which produces this snippet of configure. Why has this in the .m4 file:
"(unknown)"|0.8[1-8]*|0.89[01234])
become this in configure:
"(unknown)"|0.81-8*|0.8901234)
?
XFORMS_VERSION=$lyx_cv_xfversion
case "$lyx_cv_xfversion" in
"(unknown)"|0.81-8*|0.8901234)
lyx_error_txt="$lyx_error_txt
** Version $lyx_cv_xfversion of xforms is not compatible with LyX.
This version of LyX works best with version 1.0 (recommended) and later.
"
lyx_error=yes ;;
0.89*|0.9999*)
lyx_warning_txt="$lyx_warning_txt
== LyX should work ok with version $lyx_cv_xfversion of xforms, but
it contains many bugs that have been squashed in version 1.0.
You should consider upgrading.
"
lyx_warning=yes ;;
1.0*) ;;
fi
