[gtksourceview/wip/warning-headers] Warn when a secondary public header is #included in external code

[Sébastien Wilmet <swilmet src gnome org>]

commit b77abeb97b7b13ab91836d4947dece78dbb99e19
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Fri Jun 24 22:00:56 2016 +0200

    Warn when a secondary public header is #included in external code
    
    https://bugzilla.gnome.org/show_bug.cgi?id=755700

 gtksourceview/Makefile.am                          |    1 +
 .../completion-providers/words/Makefile.am         |    1 +
 .../words/gtksourcecompletionwords.h               |    4 ++++
 gtksourceview/gtksource.h                          |    4 ++++
 gtksourceview/gtksourcetypes.h                     |    4 ++++
 5 files changed, 14 insertions(+), 0 deletions(-)
---
diff --git a/gtksourceview/Makefile.am b/gtksourceview/Makefile.am
index 90f6b0a..eb59658 100644
--- a/gtksourceview/Makefile.am
+++ b/gtksourceview/Makefile.am
@@ -7,6 +7,7 @@ endif
 AM_CPPFLAGS =                          \
        -DDATADIR=\""$(datadir)"\"      \
        -DG_LOG_DOMAIN=\"GtkSourceView\"\
+       -DGTK_SOURCE_COMPILATION        \
        -I$(top_builddir)               \
        -I$(top_srcdir) -I$(srcdir)     \
        $(DISABLE_DEPRECATED_CFLAGS)    \
diff --git a/gtksourceview/completion-providers/words/Makefile.am 
b/gtksourceview/completion-providers/words/Makefile.am
index f0b23b1..97bf31e 100644
--- a/gtksourceview/completion-providers/words/Makefile.am
+++ b/gtksourceview/completion-providers/words/Makefile.am
@@ -3,6 +3,7 @@
 AM_CPPFLAGS =                          \
        -DDATADIR=\""$(datadir)"\"      \
        -DG_LOG_DOMAIN=\"GtkSourceView\"\
+       -DGTK_SOURCE_COMPILATION        \
        -I$(top_srcdir) -I$(srcdir)     \
        $(DISABLE_DEPRECATED_CFLAGS)    \
        $(WARN_CFLAGS)                  \
diff --git a/gtksourceview/completion-providers/words/gtksourcecompletionwords.h 
b/gtksourceview/completion-providers/words/gtksourcecompletionwords.h
index e803099..f28fd6a 100644
--- a/gtksourceview/completion-providers/words/gtksourcecompletionwords.h
+++ b/gtksourceview/completion-providers/words/gtksourcecompletionwords.h
@@ -22,9 +22,13 @@
 #ifndef GTK_SOURCE_COMPLETION_WORDS_H
 #define GTK_SOURCE_COMPLETION_WORDS_H
 
+#define GTK_SOURCE_H_INSIDE
+
 #include <gtksourceview/gtksourcecompletionprovider.h>
 #include <gtk/gtk.h>
 
+#undef GTK_SOURCE_H_INSIDE
+
 G_BEGIN_DECLS
 
 #define GTK_SOURCE_TYPE_COMPLETION_WORDS               (gtk_source_completion_words_get_type ())
diff --git a/gtksourceview/gtksource.h b/gtksourceview/gtksource.h
index 7d4fffe..3d330d6 100644
--- a/gtksourceview/gtksource.h
+++ b/gtksourceview/gtksource.h
@@ -20,6 +20,8 @@
 #ifndef GTK_SOURCE_H
 #define GTK_SOURCE_H
 
+#define GTK_SOURCE_H_INSIDE
+
 #include <gtksourceview/gtksourcetypes.h>
 #include <gtksourceview/gtksourcebuffer.h>
 #include <gtksourceview/gtksourcecompletioncontext.h>
@@ -59,4 +61,6 @@
 #include <gtksourceview/gtksourceview-enumtypes.h>
 #include <gtksourceview/gtksourceautocleanups.h>
 
+#undef GTK_SOURCE_H_INSIDE
+
 #endif /* GTK_SOURCE_H */
diff --git a/gtksourceview/gtksourcetypes.h b/gtksourceview/gtksourcetypes.h
index 3038900..7c1ff8d 100644
--- a/gtksourceview/gtksourcetypes.h
+++ b/gtksourceview/gtksourcetypes.h
@@ -22,6 +22,10 @@
 #ifndef GTK_SOURCE_TYPES_H
 #define GTK_SOURCE_TYPES_H
 
+#if !defined (GTK_SOURCE_H_INSIDE) && !defined (GTK_SOURCE_COMPILATION)
+#warning "Only <gtksourceview/gtksource.h> can be included directly."
+#endif
+
 #include <gio/gio.h>
 #include <gtksourceview/gtksourceversion.h>