Update.

* elf/Makefile (tests): Add filter.  Add rules to generate filter.
	* elf/filter.c: New file.
	* elf/filtmod1.c: New file.
	* elf/filtmod2.c: New file.

elf/filter.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+#include <string.h>
+
+extern const char *foo (void);
+
+int
+main (void)
+{
+  const char *s = foo ();
+
+  printf ("called `foo' from `%s'\n", s);
+
+  return strcmp (s, "filtmod2.c");
+}