RULES: Expand @TOP@ and @ARCH@ in .plt files

Use this in Snippets.plt

configure/RULES_BUILD

@@ -380,7 +380,7 @@ endif
 # If there's a perl test script (.plt) available, use it
 %.t: ../%.plt
 	@$(RM) $@
-	$(CP) $< $@
+	$(EXPAND_TOOL) -t $(INSTALL_LOCATION) -a $(T_A) $< $@
 
 # Test programs (.t files) must be written in Perl.
 # Generate a perl program to exec the real test binary.

test/tools/Snippets.plt

@@ -19,7 +19,7 @@ sub mksnip {
 }
 
 sub assemble {
-    my @cmd = ( 'perl', '../../../src/tools/assembleSnippets.pl', '-o', "out$$" );
+    my @cmd = ( 'perl', '@TOP@/bin/@ARCH@/assembleSnippets.pl', '-o', "out$$" );
     push @cmd, @_;
     system(@cmd);
     open(my $fh, '<', "out$$") or die "can't open out$$ : $!";