[gtkmm-documentation] docs/tutorial/Makefile.am: Modify for Infrastructure/damned-lies

[Kjell Ahlstedt <kjellahl src gnome org>]

commit 91fe9d60a8ee540780853220164c0fbf72d94835
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Fri Oct 30 17:11:36 2020 +0100

    docs/tutorial/Makefile.am: Modify for Infrastructure/damned-lies
    
    * docs/tutorial/Makefile.am: Include help-files.am.
    * docs/tutorial/help-files.am: New file.
    
    A better fix for suiting damned-lies. Depends on a recent patch in
    damned-lies. See Infrastructure/damned-lies#58

 docs/tutorial/Makefile.am   | 11 +++++------
 docs/tutorial/help-files.am |  9 +++++++++
 2 files changed, 14 insertions(+), 6 deletions(-)
---
diff --git a/docs/tutorial/Makefile.am b/docs/tutorial/Makefile.am
index eee16e5..f4ce86e 100644
--- a/docs/tutorial/Makefile.am
+++ b/docs/tutorial/Makefile.am
@@ -20,13 +20,12 @@ DOCBOOK_STYLESHEET_EPUB ?= http://docbook.sourceforge.net/release/xsl/current/ep
 
 HELP_ID = gtkmm-tutorial
 
-# This dummy value will perhaps make Infrastructure/damned-lies create a .pot file
-# from index-in.docbook and ignore index.docbook.
+# HELP_FILES is defined in an included file instead of in Makefile.am itself.
+# Then DocFormat.source_files() in Infrastructure/damned-lies/stats/utils.py
+# won't find it. That's a good thing. The help file is not stored in the git repo.
+# damned-lies is confused, if it finds the file name but does not find the file.
 # https://gitlab.gnome.org/Infrastructure/damned-lies/-/issues/58
-HELP_FILES = $(NULL)
-
-# The 'make' command uses the last defined value.
-HELP_FILES = index.docbook
+include $(srcdir)/help-files.am
 
 HELP_MEDIA =                                   \
        figures/aspectframe.png                 \
diff --git a/docs/tutorial/help-files.am b/docs/tutorial/help-files.am
new file mode 100644
index 0000000..6028d2a
--- /dev/null
+++ b/docs/tutorial/help-files.am
@@ -0,0 +1,9 @@
+## This file is part of gtkmm-documentation.
+
+# When this line is located in a file included from Makefile.am instead of
+# in Makefile.am itself, DocFormat.source_files() in
+# Infrastructure/damned-lies/stats/utils.py won't find it.
+# https://gitlab.gnome.org/Infrastructure/damned-lies/-/issues/58
+
+HELP_FILES = index.docbook
+