docs: Minor build improvements

Don't use "set -x" for the figs rule.  It doesn't take effect in the recursive
make environment.

Turn the HTML manpage comments into makefile comments, not shell comments.
This saves 3x shell invocations per manpage.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Release-acked-by: Paul Durrant <paul@xen.org>

docs/Makefile

@@ -58,7 +58,7 @@ txt: $(DOC_TXT)
 .PHONY: figs
 figs:
 ifneq ($(FIG2DEV),)
-	set -x; $(MAKE) -C figs
+	$(MAKE) -C figs
 else
 	@echo "fig2dev (transfig) not installed; skipping figs."
 endif
@@ -105,12 +105,12 @@ else
 endif
 
 # HTML manpages
+# sed used to fix up links between man-pages
+# 1) L<xl(1)> -> L<xl(1)|relative:xl.1.html>
+# 2) <a href="relative:xl.1.html"> -> <a href="xl.1.html">
 html/man/%.$(1).html: man/%.$(1).pod Makefile
 ifneq ($(POD2HTML),)
 	@$(INSTALL_DIR) $$(@D)
-	# Fix up links between man-pages
-	# 1) L<xl(1)> -> L<xl(1)|relative:xl.1.html>
-	# 2) <a href="relative:xl.1.html"> -> <a href="xl.1.html">
 	sed -r -e 's%L<([^>]+)\(([1-9])\)>%L<\1(\2)|relative:\1.\2.html>%g' $$< | \
 		$(POD2HTML) | \
 		sed -r -e 's%( href=")relative:%\1%g' > $$@