build: Build and install manual pages.

* configure.ac: Use 'AM_MISSING_PROG' for 'help2man'.
* doc.am (subcommand-manual-target, SUBCOMMANDS, dist_man1_MANS): New
  variables.
  (doc/guix-$(1).1, doc/guix.1): New targets.

configure.ac

@@ -182,6 +182,9 @@ dnl `dot' (from the Graphviz package) is only needed for maintainers.
 dnl See `HACKING' for more info.
 AM_MISSING_PROG([DOT], [dot])
 
+dnl Manual pages.
+AM_MISSING_PROG([HELP2MAN], [help2man])
+
 AC_CONFIG_FILES([Makefile
                  po/guix/Makefile.in
                  po/packages/Makefile.in

doc.am

@@ -65,3 +65,40 @@ DOT_OPTIONS =					\
 pdf-local: $(top_srcdir)/doc/images/bootstrap-graph.pdf
 info-local: $(top_srcdir)/doc/images/bootstrap-graph.png
 ps-local: $(top_srcdir)/doc/images/bootstrap-graph.eps
+
+
+# Manual pages.
+
+doc/guix.1: $(top_builddir)/scripts/guix
+	-LANGUAGE= $(top_builddir)/pre-inst-env	\
+	  $(HELP2MAN) --output="$@" guix
+
+define subcommand-manual-target
+
+doc/guix-$(1).1: $(top_srcdir)/guix/scripts/$(1).scm
+	-LANGUAGE= $(top_builddir)/pre-inst-env		\
+	  $(HELP2MAN) --output="$$@" "guix $(1)"
+
+endef
+
+SUBCOMMANDS :=					\
+  archive					\
+  build						\
+  download					\
+  environment					\
+  gc						\
+  hash						\
+  import					\
+  lint						\
+  package					\
+  publish					\
+  pull						\
+  refresh					\
+  system
+
+$(eval $(foreach subcommand,$(SUBCOMMANDS),			\
+          $(call subcommand-manual-target,$(subcommand))))
+
+dist_man1_MANS =				\
+  doc/guix.1					\
+  $(SUBCOMMANDS:%=doc/guix-%.1)