2001-08-03 Richard Boulton <richard@tartarus.org>

	* automake.in (value_to_list): Check for whether $from is defined,
	rather than whether it is true, so that empty $froms are allowed in
	substitution reference patterns.

	* tests/substref.test: New file: test behavior of substitution
	references when the $from side of the substitution is empty.
	* tests/Makefile.am (TESTS): Added substref.test.

1 files changed, 1 insertions, 1 deletions

diff --git a/automake.in b/automake.in
index 125829bba..cecb270ff 100755
--- a/automake.in
+++ b/automake.in
@@ -6113,7 +6113,7 @@ sub value_to_list
 	    @temp_list = &variable_value_as_list_worker ($1, $cond, $var);
 
 	    # Now rewrite the value if appropriate.
-	    if ($from)
+	    if (defined $from)
 	    {
 		grep (s/$from$/$to/, @temp_list);
 	    }