From 205337fed1d00c9b2c86fbc2c676cebed8ebad9f Mon Sep 17 00:00:00 2001
From: Nicola Fontana <ntd@entidi.it>
Date: Tue, 25 May 2021 21:46:56 +0200
Subject: [PATCH] Do not define DIST_SUBDIRS when not needed

DIST_SUBDIRS is automatically populated with all possible values of
SUBDIRS in all conditions:

    https://www.gnu.org/software/automake/manual/html_node/SUBDIRS-vs-DIST_005fSUBDIRS.html

This means it is usually not needed to explicitely set it but in
examples/, where some dirs are never added to SUBDIRS.
---
 Makefile.am          | 23 +++++++----------------
 devices/Makefile.am  |  6 ------
 examples/Makefile.am |  2 ++
 3 files changed, 9 insertions(+), 22 deletions(-)

diff --git a/Makefile.am b/Makefile.am
index fea26e54..42ff854c 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -38,8 +38,9 @@ SUBDIRS = \
 	script
 
 if ENABLE_KERNEL
-SUBDIRS += devices
-SUBDIRS += master
+SUBDIRS += \
+	devices \
+	master
 endif
 
 if BUILD_TOOL
@@ -47,26 +48,16 @@ SUBDIRS += tool
 endif
 
 if ENABLE_USERLIB
-SUBDIRS += lib
+# userspace examples depend on lib/
+SUBDIRS += \
+	lib \
+	examples
 endif
 
 if ENABLE_TTY
 SUBDIRS += tty
 endif
 
-# userspace example depends on lib/
-SUBDIRS += examples
-
-DIST_SUBDIRS = \
-	devices \
-	examples \
-	include \
-	lib \
-	m4 \
-	master \
-	script \
-	tool \
-	tty
 
 noinst_HEADERS = \
 	globals.h
diff --git a/devices/Makefile.am b/devices/Makefile.am
index a7925084..28342dfd 100644
--- a/devices/Makefile.am
+++ b/devices/Makefile.am
@@ -33,12 +33,6 @@ SUBDIRS = \
 	e1000e \
 	igb
 
-DIST_SUBDIRS = \
-	ccat \
-	e1000 \
-	e1000e \
-	igb
-
 # using HEADERS to enable tags target
 noinst_HEADERS = \
 	8139too-2.6.13-ethercat.c \
diff --git a/examples/Makefile.am b/examples/Makefile.am
index 6d79af16..0ed68a0e 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -54,6 +54,8 @@ SUBDIRS += \
 endif
 endif
 
+# Here DIST_SUBDIRS needs to be explicitely defined because
+# dc_rtai, mini and rtai are never added to `SUBDIRS`
 DIST_SUBDIRS = \
 	dc_rtai \
 	dc_user \