Docs installation

Try to install discord-help into bitlbee's datadir. It should work
better once we have datadir in bitlbee.pc

Makefile.am

@@ -15,4 +15,4 @@
 
 AUTOMAKE_OPTIONS = foreign
 ACLOCAL_AMFLAGS = -Im4
-SUBDIRS = src
+SUBDIRS = src doc

configure.ac

@@ -73,5 +73,23 @@ AS_IF(
 
 AC_SUBST([plugindir])
 
-AC_CONFIG_FILES([Makefile src/Makefile])
+AC_ARG_WITH([bdatadir],
+    [AS_HELP_STRING([--with-bdatadir], [BitlBee data directory])],
+    [bdatadir="$with_bdatadir"]
+)
+
+AS_IF(
+    [test -z "$bdatadir"],
+    [PKG_CHECK_VAR(
+        [BITLBEE_DATADIR],
+        [bitlbee],
+        [datadir],
+        [datadir="$BITLBEE_DATADIR"],
+        [datadir="$datarootdir/bitlbee"]
+    )]
+)
+
+AC_SUBST([datadir])
+
+AC_CONFIG_FILES([Makefile src/Makefile doc/Makefile])
 AC_OUTPUT

doc/Makefile.am

@@ -0,0 +1,26 @@
+# Copyright 2017 Artem Savkov <artem.savkov@gmail.com>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+EXTRA_DIST = discord-help.txt
+
+install-data-local:
+	if [ -f $(DESTDIR)$(datadir)/help.txt ]; then \
+		for file in $(EXTRA_DIST); do \
+			$(INSTALL) -m 644 $(srcdir)/$$file $(DESTDIR)$(datadir)/; \
+		done \
+	else \
+		echo "Detected dir $(DESTDIR)$(datadir) is not bitlbee's data dir"; \
+		echo "Skipping help install"; \
+	fi