[gtkmm-documentation] Fix 'make distcheck'

[Kjell Ahlstedt <kjellahl src gnome org>]

commit 0d5d2344dedee5fb2820bed672c415a32b1443c5
Author: Kjell Ahlstedt <kjell ahlstedt bredband net>
Date:   Sun Dec 28 10:26:03 2014 +0100

    Fix 'make distcheck'
    
    * docs/tutorial/Makefile.am: Let yelp-tools decide when subdirectories shall
    be created. Otherwise 'make distcheck' fails. When the build directory is
    different from the source directory, yelp-tools don't expect the language
    subdirectories to be unconditionally created in the build directory.

 docs/tutorial/Makefile.am |   11 +++++++----
 1 files changed, 7 insertions(+), 4 deletions(-)
---
diff --git a/docs/tutorial/Makefile.am b/docs/tutorial/Makefile.am
index 4102ece..d23820c 100644
--- a/docs/tutorial/Makefile.am
+++ b/docs/tutorial/Makefile.am
@@ -103,6 +103,12 @@ HELP_MEDIA =                                       \
        figures/treeview_tree.png               \
        figures/update_ui.png
 
+# Do not define the environment variable LINGUAS.
+# If the environment variable LINGUAS exists, YELP_HELP_RULES generate
+# make rules for creating files only for languages that are listed in both
+# LINGUAS and HELP_LINGUAS, but this Makefile.am assumes that files for
+# all languages in HELP_LINGUAS can be created.
+
 HELP_LINGUAS = de el es fr pt_BR sl zh_CN
 
 MAINTAINERCLEANFILES = html/*.html $(srcdir)/html/*.html
@@ -158,7 +164,7 @@ dist_tutorial_icons_DATA =  \
        icons/warning.png
 
 
-all-local: $(HELP_LINGUAS) $(addsuffix /index.docbook,C $(HELP_LINGUAS)) html/index.html
+all-local: $(addsuffix /index.docbook,C $(HELP_LINGUAS)) html/index.html
 
 install-data-local: install-tutorial
 
@@ -174,9 +180,6 @@ uninstall-tutorial:
        rm -f '$(DESTDIR)$(tutorial_htmldir)'/*.html
        rm -f '$(DESTDIR)$(tutorial_htmldir)/style.css'
 
-$(HELP_LINGUAS):
-       @$(MKDIR_P) $@
-
 # Create a html generation of the C locale's version of the DocBook,
 # using our custom stylesheet and graphics:
 html/index.html: $(srcdir)/C/index.docbook