Problems with the new Var code

[Akim Demaille]

Notice the Perl warning below.  Maybe you could catch Perl warnings (I
think __SIGNAL__, or whatever its name, can do that) and make them
actually errors?  Or is it simply that modules lack their use strict?

src/am/tests % VERBOSE=e ./lisp2.test                             nostromo 9:11
=== Running test ./lisp2.test
/home/akim/src/am/tests/testSubDir
1
Use of uninitialized value in concatenation (.) or string at 
/home/akim/src/am/tests/../lib/Automake/Variable.pm line 1228.
Makefile.am:1: Emacs Lisp sources seen but `EMACS' is undefined
Makefile.am:1: 
Makefile.am:1: The usual way to define `EMACS' is to add `AM_PATH_LISPDIR'
Makefile.am:1: to `' and run `aclocal' and `autoconf' again.
Use of uninitialized value in concatenation (.) or string at 
/home/akim/src/am/tests/../lib/Automake/Variable.pm line 1228.
Makefile.am:1: Emacs Lisp sources seen but `lispdir' is undefined
Makefile.am:1: 
Makefile.am:1: The usual way to define `lispdir' is to add `AM_PATH_LISPDIR'
Makefile.am:1: to `' and run `aclocal' and `autoconf' again.
Makefile.am:1: required file `./elisp-comp' not found
Makefile.am:1: The usual way to define `EMACS' is to add `AM_PATH_LISPDIR'
Makefile.am:1: The usual way to define `lispdir' is to add `AM_PATH_LISPDIR'
2
Use of uninitialized value in concatenation (.) or string at 
/home/akim/src/am/tests/../lib/Automake/Variable.pm line 1228.
Makefile.am:2: Emacs Lisp sources seen but `EMACS' is undefined
Makefile.am:2: 
Makefile.am:2: The usual way to define `EMACS' is to add `AM_PATH_LISPDIR'
Makefile.am:2: to `' and run `aclocal' and `autoconf' again.
Makefile.am:2: installing `./elisp-comp'
Makefile.am:2: The usual way to define `EMACS' is to add `AM_PATH_LISPDIR'
3
Use of uninitialized value in concatenation (.) or string at 
/home/akim/src/am/tests/../lib/Automake/Variable.pm line 1228.
Makefile.am:2: Emacs Lisp sources seen but `lispdir' is undefined
Makefile.am:2: 
Makefile.am:2: The usual way to define `lispdir' is to add `AM_PATH_LISPDIR'
Makefile.am:2: to `' and run `aclocal' and `autoconf' again.
Makefile.am:2: The usual way to define `lispdir' is to add `AM_PATH_LISPDIR'
4


Also, while on $configure_ac: Is it really good to initialize it to a
valid value '' instead of keeping it undef?

~/src/am % grep 'configure_ac.*=' automake.in                     nostromo 9:12
my $configure_ac = '';
    $configure_ac = find_configure_ac;