Re: [PATCH 6/6] use print or printf or cat as $ECHO

[Paolo Bonzini]

> 1) I don't have access to systems that are old or weird enough to check
> if the performance penalty will happen often.  What do you think?
> 
> 2) If ksh had a way to print without interpreting escapes *and dashes*,
> I'd be glad to add it; do you know one?

I thought of one after lunch: "print -r -- FOO".  This way we can print
without forking on bash, zsh, ksh, ash/dash.

So here is a resubmission of patch 6/6.

Paolo

diff --git a/libltdl/config/ltmain.m4sh b/libltdl/config/ltmain.m4sh
index e3627b0..28f50cd 100644
--- a/libltdl/config/ltmain.m4sh
+++ b/libltdl/config/ltmain.m4sh
@@ -92,8 +92,13 @@ fi
 BIN_SH=xpg4; export BIN_SH # for Tru64
 DUALCASE=1; export DUALCASE # for MKS sh
 
-# In case there is no working printf in the path
-eval "$lt_func_ECHO"
+# A function that is used when printf is not a builtin.
+func_fallback_echo ()
+{
+  cat <<_LTECHO_EOF
+$1
+_LTECHO_EOF
+}
 
 # NLS nuisances: We save the old values to restore during execute mode.
 # Only set LANG and LC_ALL to C if already set.
@@ -2340,16 +2345,18 @@ if test \"\$libtool_install_magic\" = \"$magic\"; then
 else
   # When we are sourced in execute mode, \$file and \$ECHO are already set.
   if test \"\$libtool_execute_magic\" != \"$magic\"; then
-    file=\"\$0\"
-    # Make sure echo works."
+    file=\"\$0\""
 
-    qlt_cmd_ECHO=`$ECHO "X$lt_cmd_ECHO" | $Xsed -e "$sed_quote_subst"`
-    qlt_func_ECHO=`$ECHO "X$lt_func_ECHO" | $Xsed -e "$sed_quote_subst"`
     qECHO=`$ECHO "X$ECHO" | $Xsed -e "$sed_quote_subst"`
-       $ECHO "\
-    lt_cmd_ECHO=\"$qlt_cmd_ECHO\"
-    lt_func_ECHO=\"$qlt_func_ECHO\"
-    eval \"\$lt_func_ECHO\"
+    $ECHO "\
+
+# A function that is used when printf is not a builtin.
+func_fallback_echo ()
+{
+  cat <<_LTECHO_EOF
+\$1
+_LTECHO_EOF
+}
     ECHO=\"$qECHO\"
   fi\
 
diff --git a/libltdl/m4/libtool.m4 b/libltdl/m4/libtool.m4
index 4c4aa0b..b221749 100644
--- a/libltdl/m4/libtool.m4
+++ b/libltdl/m4/libtool.m4
@@ -526,7 +526,13 @@ LTCC='$LTCC'
 LTCFLAGS='$LTCFLAGS'
 compiler='$compiler_DEFAULT'
 
-eval "\$lt_func_ECHO"
+# Used when printf is not a builtin.
+func_fallback_echo ()
+{
+  cat <<_LTECHO_EOF
+\$[]1
+_LTECHO_EOF
+}
 
 # Quote evaled strings.
 for var in lt_decl_all_varnames([[ \
@@ -1069,74 +1075,37 @@ m4_define([_LT_SHELL_INIT],
 ])])# _LT_SHELL_INIT
 
 
-# _LT_DETECT_ECHO_BACKSLASH
-# -----------------------------
-# Find a working printf (either a program or a shell builtin)
-# that can be used to print values without interpreting backslashes
-# or strings with a leading `-'.
-m4_defun([_LT_DETECT_ECHO_BACKSLASH],
+
+# _LT_PROG_ECHO_BACKSLASH
+# -----------------------
+# Find how we can fake an echo command that does not interpret backslash.
+# In particular, with Autoconf 2.60 or later we add some code to the start
+# of the generated configure script which will find a shell with a builtin
+# printf (which we can use as an echo command).
+m4_defun([_LT_PROG_ECHO_BACKSLASH],
 
[ECHO='\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'
 ECHO=$ECHO$ECHO$ECHO$ECHO$ECHO
 ECHO=$ECHO$ECHO$ECHO$ECHO$ECHO$ECHO
 
-AC_MSG_CHECKING([for a working printf])
+AC_MSG_CHECKING([how to print strings])
 if test "X`printf %s $ECHO`" = "X$ECHO"; then
   ECHO='printf %s\n'
-
 else
-  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
-  for as_dir in /bin$PATH_SEPARATOR/usr/bin$PATH_SEPARATOR$PATH
-  do
-    IFS=$as_save_IFS
-    test "x$as_dir" = x && continue
-    test -f "$as_dir/printf" || test -f "$as_dir/printf.exe" || continue
-    test "X`$as_dir/printf %s $ECHO`" = "X$ECHO" &&
-      { ECHO=$as_dir/printf' %s\n' ; break; }
-  done
-  case "$ECHO" in
-    */printf*) ;;
-    *) 
-      lt_cmd_ECHO="printf %s\\\\n \"\$[]1\""
-      as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
-      for as_dir in /bin$PATH_SEPARATOR/usr/bin$PATH_SEPARATOR$PATH
-      do
-        IFS=$as_save_IFS
-        test "x$as_dir" = x && continue
-        for as_base in sh bash ksh zsh sh5; do
-          as_shell=$as_dir/$as_base
-          test -f "$as_shell" || test -f "$as_shell.exe" || continue
-         lt_func_ECHO='func_do_echo () { '$as_shell' -c "$lt_cmd_ECHO" x 
"$[]1";}'
-          (lt_out=`$as_shell -c "
-               PATH=/tmp/nonexistent; export PATH;
-               FPATH=/tmp/nonexistent; export FPATH;
-               printf %s \"\\$[]1\"" lt_echo "$ECHO"`
-          test "X$lt_out" = "X$ECHO") &&
-            { eval "$lt_func_ECHO"; ECHO=func_do_echo; break 2; }
-        done
-      done
-  esac
+  # Used when printf is not a builtin.
+  func_fallback_echo ()
+  {
+    cat <<_LTECHO_EOF
+$[]1
+_LTECHO_EOF
+  }
+  ECHO='func_fallback_echo'
 fi
 
 case "$ECHO" in
-  printf*) AC_MSG_RESULT([shell builtin]) ;;
-  */printf*) AC_MSG_RESULT([$as_dir/printf]) ;;
-  func_do_echo) AC_MSG_RESULT([$as_shell builtin]) ;;
-  *) AC_MSG_RESULT([not found])
-    AC_MSG_ERROR([cannot find a working printf]) ;;
+  printf*) AC_MSG_RESULT([printf]) ;;
+  *) AC_MSG_RESULT([cat]) ;;
 esac
 
-_LT_DECL([], [lt_cmd_ECHO], [1], [Used if there is no working printf in the 
path])
-_LT_DECL([], [lt_func_ECHO], [1], [Used if there is no working printf in the 
path])
-])
-
-# _LT_PROG_ECHO_BACKSLASH
-# -----------------------
-# Add some code to the start of the generated configure script which
-# will find a printf which doesn't interpret backslashes, and
-# which we can use as an echo command.  If possible, find a builtin.
-m4_defun([_LT_PROG_ECHO_BACKSLASH],
-[m4_require([_LT_DECL_SED])dnl
-m4_require([_LT_DETECT_ECHO_BACKSLASH])dnl
 m4_ifdef([_AS_DETECT_SUGGESTED],
 [_AS_DETECT_SUGGESTED([
   
ECHO='\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'