The configure script is broken if the selected layout begins on the first
line of config.layout.

To reproduce:

cd httpd-2.0.43
mv config.layout config.layout.orig
sed -n '13,34p' config.layout.orig | tee config.layout
./configure
# the result is an exceedingly unobvious error from the APR sub configure
# script which complains about "--bindir: NONE/bin"
sed -n '12,34p' config.layout.orig | tee config.layout
./configure
# works

This is with GNU Sed 4.0.4 which is relevent because the problem is with the
sed program that configure uses to parse config.layout.

The following patch (which i will also attach, if the system lets me) fixes
the problem for me.

--- acinclude.m4.orig	2002-12-27 01:26:56.000000000 -0500
+++ acinclude.m4	2002-12-27 01:27:28.000000000 -0500
@@ -275,7 +275,7 @@
   fi
   pldconf=./config.pld
   changequote({,})
-  sed -e "1,/[ 	]*<[lL]ayout[ 	]*$2[ 	]*>[ 	]*/d" \
+  sed -e "0,/[ 	]*<[lL]ayout[ 	]*$2[ 	]*>[ 	]*/d" \
       -e '/[ 	]*<\/Layout>[ 	]*/,$d' \
       -e "s/^[ 	]*//g" \
       -e "s/:[ 	]*/=\'/g" \

I am tempted to indulge in a rant about the wisdom of using configure args
instead of weird config files in this situation but this bug report is hardly
the place.

I will however indulge in a suggestion. Something like:
if [ ! -s "$pldconf" ];then
    echo "*** Error: unable to find layout \"$LAYOUT\""
    exit 1
fi
at the logical place would give a much clearer error message.