GitLab

	copy_text_properties.

	* 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.