autotools: be more templated when getting list of doc dist files

Distribute asciidoc sources for all manpages instead of remembering to
add files to both variables. Fixes regression in
377d47142f which broke building the
website from a dist tarball:

make: *** No rule to make target 'pacman-conf.8.html', needed by 'html'.  Stop.

(Technically this regression is already fixed by commit
942b909829, but this is just going to keep
happening, I suspect, so we should fix the root cause.)

Signed-off-by: Eli Schwartz <eschwartz@archlinux.org>
Signed-off-by: Allan McRae <allan@archlinux.org>

doc/Makefile.am

@@ -21,6 +21,7 @@ MANPAGES = \
 DOXYGEN_MANS = $(wildcard man3/*.3)
 
 HTML_MANPAGES = $(addsuffix .html,$(MANPAGES))
+ASCIIDOC_MANPAGES = $(addsuffix .asciidoc,$(MANPAGES))
 
 HTML_OTHER = \
 	index.html \
@@ -36,24 +37,12 @@ EXTRA_DIST = \
 	meson.build \
 	asciidoc.conf \
 	asciidoc-override.css \
-	alpm-hooks.5.asciidoc \
-	pacman.8.asciidoc \
-	makepkg.8.asciidoc \
-	makepkg-template.1.asciidoc \
-	repo-add.8.asciidoc \
-	vercmp.8.asciidoc \
-	pacman-key.8.asciidoc \
-	PKGBUILD.5.asciidoc \
 	PKGBUILD-example.txt \
-	makepkg.conf.5.asciidoc \
-	pacman.conf.5.asciidoc \
-	BUILDINFO.5.asciidoc \
-	pacman-conf.8.asciidoc \
-	libalpm.3.asciidoc \
 	footer.asciidoc \
 	index.asciidoc \
 	submitting-patches.asciidoc \
 	translation-help.asciidoc \
+	$(ASCIIDOC_MANPAGES) \
 	$(MANPAGES) \
 	$(DOXYGEN_MANS)