Do not quote $SHELL when rerunning configure

[Ralf Wildenhues]

Hello Paul, all,

in commit 1be64afa5b45bf6cd82a0d118d8442527d9296fe, you quoted '$SHELL'
in the code below.  That strikes me as weird, because it prevents me
from doing funky debugging like this:
  CONFIG_SHELL='/bin/sh -x' /bin/sh -x ./configure
  ./config.status --recheck             # I'd like it to use sh -x

I /think/ all other instances of SHELL or CONFIG_SHELL already allow
more than one word.  I am not aware of any system for which one of the
normally-used shells has an absolute file name containing a space.
I don't really think we need to cater to w32 users actively trying to
shoot themselves in the foot.

This patch (trivially) conflicts with the --recursion=new-only patch.

Thanks,
Ralf

    config.status: do not quote $SHELL when rerunning configure.
    
    * lib/autoconf/status.m4 (_AC_OUTPUT_CONFIG_STATUS): Allow
    $SHELL to contain more than one word, when rerunning configure,
    for debugging purposes like CONFIG_SHELL='/bin/sh -x'.

diff --git a/lib/autoconf/status.m4 b/lib/autoconf/status.m4
index 00cbb31..f50f503 100644
--- a/lib/autoconf/status.m4
+++ b/lib/autoconf/status.m4
@@ -1547,7 +1547,7 @@ cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 dnl Check this before opening the log, to avoid a bug on MinGW,
 dnl which prohibits the recursive instance from truncating an open log.
 if \$ac_cs_recheck; then
-  set X '$SHELL' '$[0]' $ac_configure_args \$ac_configure_extra_args 
--no-create --recursion=new-only
+  set X $SHELL '$[0]' $ac_configure_args \$ac_configure_extra_args --no-create 
--recursion=new-only
   shift
   \AS_ECHO(["running CONFIG_SHELL=$SHELL \$[*]"]) >&AS_MESSAGE_FD
   CONFIG_SHELL='$SHELL'