Tweak Makefile emacs-module.h handling

* Makefile.in (install-arch-indep, uninstall): Respect DESTDIR.
Handle whitespace.  Remove non-portable mkdir argument.

Makefile.in

@@ -563,8 +563,8 @@ set_installuser=for installuser in $${LOGNAME} $${USERNAME} $${USER} \
 ## See also these comments from 2004 about cp -r working fine:
 ## https://lists.gnu.org/r/autoconf-patches/2004-11/msg00005.html
 install-arch-indep: lisp install-info install-man ${INSTALL_ARCH_INDEP_EXTRA}
-	umask 022 && $(MKDIR_P) -m 0755 $(includedir)
-	$(INSTALL_DATA) src/emacs-module.h $(includedir)/emacs-module.h
+	umask 022 && $(MKDIR_P) "$(DESTDIR)$(includedir)"
+	$(INSTALL_DATA) src/emacs-module.h "$(DESTDIR)$(includedir)/emacs-module.h"
 	-set ${COPYDESTS} ; \
 	unset CDPATH; \
 	$(set_installuser); \
@@ -748,7 +748,7 @@ install-strip:
 ###
 ### Don't delete the lisp and etc directories if they're in the source tree.
 uninstall: uninstall-$(NTDIR) uninstall-doc
-	rm -f $(includedir)/emacs-module.h
+	rm -f "$(DESTDIR)$(includedir)/emacs-module.h"
 	$(MAKE) -C lib-src uninstall
 	-unset CDPATH; \
 	for dir in "$(DESTDIR)${lispdir}" "$(DESTDIR)${etcdir}" ; do 	\