2004-04-16  Dmitry V. Levin  <address@hidden>

	* function.c (func_shell): When initializing error_prefix, check
	that reading file name is not null.  This fixes long-standing
	segfault in cases like "make 'a1=$(shell :)' 'a2:=$(a1)'".

--- make-3.81beta1/function.c.orig	2004-02-24 16:50:21 +0300
+++ make-3.81beta1/function.c	2004-04-16 13:52:03 +0400
@@ -1450,7 +1450,7 @@ func_shell (char *o, char **argv, const 
   envp = environ;
 
   /* For error messages.  */
-  if (reading_file != 0)
+  if (reading_file && reading_file->filenm)
     {
       error_prefix = (char *) alloca (strlen (reading_file->filenm)+11+4);
       sprintf (error_prefix,