align _END label, add ALIGN directive to assembler

- fixes failing memory allocator when _END label is not aligned

pcomp/emit.pas

@@ -324,7 +324,9 @@ begin
 	rewindStringList(usedUnits);
 	while nextStringListItem(usedUnits, unitName) do
 		emitInclude(unitName + UnitSuffix2);
-
+	(* _END label needs to be word-aligned because
+		it is used as the start of the heap *)
+	emitIns('.ALIGN');
 	emitLabelRaw('_END');
 end;
 

pcomp/sasm.pas

@@ -2056,6 +2056,9 @@ begin
 			operandValue := 0;
 		emitBlock(count, operandValue);
 	end
+	else
+	if lastToken.tokenText6 = '.ALIGN' then
+		alignOutput(wordSize)
 	else
 		errorExit2('Unrecognized directive', lastToken.tokenText);
 end;