sys-apps/gpet: fix documentation install path

Closes: https://bugs.gentoo.org/810766
Signed-off-by: Naohiro Aota <naota@gentoo.org>

sys-apps/gpet/gpet-0.4-r1.ebuild

@@ -1,8 +1,10 @@
-# Copyright 1999-2020 Gentoo Authors
+# Copyright 1999-2021 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 EAPI=7
 
+inherit autotools
+
 DESCRIPTION="GTK+ based TOMOYO policy editor"
 HOMEPAGE="http://en.sourceforge.jp/projects/gpet/"
 SRC_URI="mirror://sourceforge.jp/gpet/53178/${P}.tar.bz2"
@@ -21,3 +23,10 @@ DEPEND="${RDEPEND}"
 BDEPEND="
 	dev-util/intltool
 	virtual/pkgconfig"
+
+src_prepare() {
+	default
+
+	sed -i -e "/^gpetdocdir =/s!doc/gpet!doc/${P}!" Makefile.am || die
+	eautoreconf
+}