Use asciidoctor to build the manpages

debian/control

@@ -5,6 +5,7 @@ Standards-Version: 4.1.5
 Vcs-Browser: https://git.in-ulm.de/cbiedl/tang
 Vcs-Git: https://git.in-ulm.de/cbiedl/tang.git
 Build-Depends: debhelper (>= 11~),
+    asciidoctor,
     curl,
     jose,
     libhttp-parser-dev (>= 2.8.0),

debian/patches/local.use-asciidoctor-to-build-manpages.patch

@@ -0,0 +1,27 @@
+Subject: Use asciidoctor to build the manpages
+Author: Christoph Biedl <debian.axhn@manchmal.in-ulm.de>
+Date: 2018-08-11
+Bug: https://github.com/latchset/tang/issues/32
+
+--- a/Makefile.am
++++ b/Makefile.am
+@@ -32,7 +32,7 @@
+ 
+ $(top_builddir)/%.roff: %.adoc
+ 	$(MKDIR_P) $$(dirname $@)
+-	$(A2X) -f manpage $^ -D $(top_builddir)/$$(dirname $@)
++	$(A2X) --attribute reproducible --backend=manpage  $^ -D $(top_builddir)/$$(dirname $@)
+ 	$(INSTALL) -m 644 $(top_builddir)/$(@:.roff=) $(top_builddir)/$@
+ 
+ man1_MANS += doc/tang-show-keys.1
+--- a/configure.ac
++++ b/configure.ac
+@@ -75,7 +75,7 @@
+ "
+ AC_SUBST([TANG_CFLAGS])
+ 
+-AC_CHECK_PROGS(A2X, [a2x])
++AC_CHECK_PROGS(A2X, [asciidoctor])
+ 
+ if test "x$A2X" = "x"; then
+    AC_MSG_WARN([asciidoc / a2x not found -- man pages will not be generated and installed])

debian/patches/series

@@ -0,0 +1 @@
+local.use-asciidoctor-to-build-manpages.patch