* textprop.c (copy_text_properties): New function, from David

	Gillespie.
	* intervals.h: Declare copy_text_properties.
	* fns.c: #include "intervals.h".
	(Fsubstring): Copy text properties to result string.
	(concat): Copy text properties to result string.
	* ymakefile (fns.o): Note that this depends on INTERVAL_SRC.

src/intervals.h

@@ -201,6 +201,7 @@ extern Lisp_Object Ftext_properties_at ();
 extern Lisp_Object Fnext_property_change (), Fprevious_property_change ();
 extern Lisp_Object Fadd_text_properties (), Fset_text_properties ();
 extern Lisp_Object Fremove_text_properties (), Ferase_text_properties ();
+extern Lisp_Object copy_text_properties ();
 
 extern void syms_of_textprop ();