Avoid unwanted error message in configure output.

[Ralf Wildenhues]

There might be no 'print' program available, and some shells (like
FreeBSD sh) redirect that stderr only when you call the program from
a subshell.  I'm installing this to beautify configure output.

The second 'print' instance should be fine, and 'printf' can be assumed
to at least be present everywhere, I think.

Cheers,
Ralf

    Avoid unwanted error message in configure output.
    
    * libltdl/m4/libtool.m4 (_LT_PROG_ECHO_BACKSLASH): Try print
    in subshell, so eventual `print: not found' is hidden reliably.

diff --git a/libltdl/m4/libtool.m4 b/libltdl/m4/libtool.m4
index d8d6aeb..c36a6b4 100644
--- a/libltdl/m4/libtool.m4
+++ b/libltdl/m4/libtool.m4
@@ -1122,7 +1122,7 @@ ECHO=$ECHO$ECHO$ECHO$ECHO$ECHO$ECHO
 
 AC_MSG_CHECKING([how to print strings])
 # Test print first, because it will be a builtin if present.
-if test "X`print -r -- -n 2>/dev/null`" = X-n && \
+if test "X`( print -r -- -n ) 2>/dev/null`" = X-n && \
    test "X`print -r -- $ECHO 2>/dev/null`" = "X$ECHO"; then
   ECHO='print -r --'
 elif test "X`printf %s $ECHO 2>/dev/null`" = "X$ECHO"; then