may get BASH_PATH etc. from env;

--- a/lib/scripts/patch-scripts.bash	Mon Jul 12 10:32:30 1999 +0200
+++ b/lib/scripts/patch-scripts.bash	Mon Jul 12 10:38:31 1999 +0200
@@ -1,27 +1,23 @@
 #
 # $Id$
 #
-# patch-scripts.bash - relocate interpreter paths of executable scripts.
+# patch-scripts.bash - relocate interpreter paths of executable scripts and
+#   insert AUTO_BASH/AUTO_PERL values
 #
 
 ## find binaries
 
 function findbin()
 {
-  local DEFAULT="$1"
-  local BASE=$(basename "$DEFAULT")
+  local BASE="$1"
   local BINARY=""
 
   BINARY=$(type -path "$BASE")
 
   if [ -n "$BINARY" ]; then
-    echo "using $BINARY" >&2
+    echo "found $BINARY" >&2
     echo "$BINARY"
     return
-  elif [ -f "$DEFAULT" ]; then
-    echo "using $DEFAULT" >&2
-    echo "$DEFAULT"
-    return
   else
     echo "ERROR: $BASE not found!" >&2
     echo "$DEFAULT"
@@ -32,15 +28,17 @@
 
 ## main
 
-BASH=$(findbin /bin/bash)
-PERL=$(findbin /usr/bin/perl)
+[ -z "$BASH_PATH" ] && BASH_PATH=$(findbin bash)
+[ -z "$PERL_PATH" ] && PERL_PATH=$(findbin perl)
+[ -z "$AUTO_BASH" ] && AUTO_BASH="$BASH_PATH"
+[ -z "$AUTO_PERL" ] && AUTO_PERL="$PERL_PATH"
 
 for FILE in $(find . -type f -print)
 do
   if [ -x "$FILE" ]; then
-    sed -e "s:^#!.*/bash:#!$BASH:" -e "s:^#!.*/perl:#!$PERL:" \
-      -e "s:^AUTO_BASH=.*bash:AUTO_BASH=$BASH:" \
-      -e "s:^AUTO_PERL=.*perl:AUTO_PERL=$PERL:" $FILE >$FILE~~
+    sed -e "s:^#!.*/bash:#!$BASH_PATH:" -e "s:^#!.*/perl:#!$PERL_PATH:" \
+      -e "s:^AUTO_BASH=.*bash:AUTO_BASH=$AUTO_BASH:" \
+      -e "s:^AUTO_PERL=.*perl:AUTO_PERL=$AUTO_PERL:" $FILE >$FILE~~
     if cmp -s $FILE $FILE~~; then
       rm $FILE~~
     else