bash: Add bash completion

Completes commands, options, commit checksums, ref names, remotes, and file paths.

Closes: #1077
Approved by: jlebon

Makefile-bash.am

@@ -0,0 +1,21 @@
+# Makefile for bash/
+#
+# Copyright (C) 2017 Red Hat Inc.
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the
+# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+# Boston, MA 02111-1307, USA.
+
+completionsdir = @BASH_COMPLETIONSDIR@
+dist_completions_DATA = bash/ostree

Makefile.am

@@ -111,6 +111,7 @@ endif
 include Makefile-tests.am
 include Makefile-boot.am
 include Makefile-man.am
+include Makefile-bash.am
 
 release-tag:
 	cd $(srcdir) && git $(srcdir) tag -m "Release $(VERSION)" v$(VERSION)

configure.ac

@@ -88,6 +88,17 @@ AS_IF([test "$YACC" != "bison -y"], [AC_MSG_ERROR([bison not found but required]
 
 PKG_PROG_PKG_CONFIG
 
+# PKG_CHECK_VAR added to pkg-config 0.28
+m4_define_default(
+    [PKG_CHECK_VAR],
+    [AC_ARG_VAR([$1], [value of $3 for $2, overriding pkg-config])
+     AS_IF([test -z "$$1"], [$1=`$PKG_CONFIG --variable="$3" "$2"`])
+     AS_IF([test -n "$$1"], [$4], [$5])])
+
+PKG_CHECK_VAR(BASH_COMPLETIONSDIR, [bash-completion], [completionsdir], ,
+  BASH_COMPLETIONSDIR="${sysconfdir}/bash_completion.d")
+AC_SUBST(BASH_COMPLETIONSDIR)
+
 AM_PATH_GLIB_2_0(,,AC_MSG_ERROR([GLib not found]))
 
 dnl When bumping the gio-unix-2.0 dependency (or glib-2.0 in general),