Fix configure failure on recent macOS:
sed: RE error: illegal byte sequence
--- Mk/configure.orig	2011-02-21 13:14:35.000000000 -0600
+++ Mk/configure	2019-11-28 02:31:42.000000000 -0600
@@ -29,6 +29,7 @@
 echo "# The editable source of this file is in $GENERATED.in" >> $GENERATED
 echo "#" >> $GENERATED
 
+LC_CTYPE=ISO8859-1 \
 sed -e "s|SRCROOTDIR=.*|SRCROOTDIR=$SRCROOTDIR|" \
 $GENERATED.in >> $GENERATED
 
--- config/configure.orig	2012-06-04 08:01:22.000000000 -0500
+++ config/configure	2019-11-28 02:31:41.000000000 -0600
@@ -47,6 +47,7 @@
 echo "# The editable source of this file is in $GENERATED.in" >> $GENERATED
 echo "#" >> $GENERATED
 
+LC_CTYPE=ISO8859-1 \
 sed -e "s|PREFIX=.*|PREFIX=$PREFIXDIR|" \
     -e "s|SRCROOTDIR=.*|SRCROOTDIR=$SRCROOTDIR|" \
  $GENERATED.in >> $GENERATED
