[gnome-todo] build: more improvements on autotools files

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 9a42341b98141443855c07a25ca64bd40219a54d
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Sat Oct 8 12:55:35 2016 -0300

    build: more improvements on autotools files

 configure.ac        |    1 +
 plugins/Makefile.am |   14 +++++++++++++-
 2 files changed, 14 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 7c1bc26..df3ea39 100644
--- a/configure.ac
+++ b/configure.ac
@@ -136,6 +136,7 @@ echo "
         documentation: ${enable_gtk_doc}
 
     Plugins:
+        Dark theme .............. ${enable_dark_theme_plugin}
         Scheduled panel ......... ${enable_scheduled_panel_plugin}
         Score ................... ${enable_score_plugin}
         Today panel ............. ${enable_today_panel_plugin}
diff --git a/plugins/Makefile.am b/plugins/Makefile.am
index 3319b3c..eb4fdec 100644
--- a/plugins/Makefile.am
+++ b/plugins/Makefile.am
@@ -1,9 +1,21 @@
-SUBDIRS = eds dark-theme scheduled-panel today-panel
+SUBDIRS = eds
+
+if BUILD_DARK_THEME_PLUGIN
+SUBDIRS += dark-theme
+endif
+
+if BUILD_SCHEDULED_PANEL_PLUGIN
+SUBDIRS += scheduled-panel
+endif
 
 if BUILD_SCORE_PLUGIN
 SUBDIRS += score
 endif
 
+if BUILD_TODAY_PANEL_PLUGIN
+SUBDIRS += today-panel
+endif
+
 if BUILD_UNSCHEDULED_PANEL_PLUGIN
 SUBDIRS += unscheduled-panel
 endif