xfce-base/xfce4-session: Fix relying on implicit dbus header paths

Backport an upstream patch removing unnecessary use of dbus headers.
This causes the package to implicitly rely on dbus include paths being
added by pkg-config, and causes build failure in the rare case when
xfce4-session dependencies do not require dbus.

Closes: https://bugs.gentoo.org/667440
Signed-off-by: Michał Górny <mgorny@gentoo.org>

xfce-base/xfce4-session/files/xfce4-session-4.13.1-kill-dbus-includes.patch

@@ -0,0 +1,43 @@
+From 3bddf152b902d8a1e0f674b792577b2cca635c4b Mon Sep 17 00:00:00 2001
+From: Brandon Bergren <xfce@bdragon.rtk0.net>
+Date: Sun, 26 Aug 2018 10:28:05 -0400
+Subject: [PATCH] fix build failure when dbus is not in the system include path
+ (Bug #14386)
+
+The d-bus direct depenencies were taken out in 91860af3a38080,
+but the #include <dbus/dbus.h> in xfce4-session/xfsm-global.h
+and the #include <dbus/dbus-glib.h> line in xfsm-error.c got left
+in accidentally.
+---
+ xfce4-session/xfsm-error.c  | 2 --
+ xfce4-session/xfsm-global.h | 1 -
+ 2 files changed, 3 deletions(-)
+
+diff --git a/xfce4-session/xfsm-error.c b/xfce4-session/xfsm-error.c
+index 2b7f6c04..f0766f5f 100644
+--- a/xfce4-session/xfsm-error.c
++++ b/xfce4-session/xfsm-error.c
+@@ -20,8 +20,6 @@
+ #include <config.h>
+ #endif
+ 
+-#include <dbus/dbus-glib.h>
+-
+ #include <xfce4-session/xfsm-error.h>
+ 
+ #define XFSM_DBUS_NAME "org.xfce.SessionManager"
+diff --git a/xfce4-session/xfsm-global.h b/xfce4-session/xfsm-global.h
+index d4587123..610d5bf7 100644
+--- a/xfce4-session/xfsm-global.h
++++ b/xfce4-session/xfsm-global.h
+@@ -27,7 +27,6 @@
+ #include <X11/SM/SMlib.h>
+ 
+ #include <xfce4-session/xfsm-splash-screen.h>
+-#include <dbus/dbus.h>
+ 
+ typedef struct _FailsafeClient FailsafeClient;
+ struct _FailsafeClient
+-- 
+2.19.0
+

xfce-base/xfce4-session/xfce4-session-4.13.1.ebuild

@@ -44,6 +44,10 @@ PATCHES=(
 # TODO: this patch needs updating for the new version, and finding
 # upstream bug.
 #	"${FILESDIR}"/${PN}-4.12.1-light-locker_support_to_xflock4.patch
+
+	# fix building with no dbus dependency
+	# https://bugs.gentoo.org/667440
+	"${FILESDIR}"/xfce4-session-4.13.1-kill-dbus-includes.patch
 )
 
 src_configure() {