[gegl] Add G_{BEGIN,END}_DECLS guards to chant/plugin headers

[Jon Nordby <jonnor src gnome org>]

commit 9d4e3d1621dd4228d571805ff647e5889c803491
Author: Jon Nordby <jononor gmail com>
Date:   Fri Aug 19 22:59:01 2011 +0200

    Add G_{BEGIN,END}_DECLS guards to chant/plugin headers
    
    Without these C++ compilers will interpret the definitions as
    C++ which can lead to symbol mismatches due to mangling, et.c.
    
    For compatability with older gegl versions, consumers can
    use an extern "C" block around the include statement instead.

 gegl/gegl-chant.h  |    2 ++
 gegl/gegl-plugin.h |    3 +++
 2 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/gegl/gegl-chant.h b/gegl/gegl-chant.h
index 1dd1a24..1be7f37 100644
--- a/gegl/gegl-chant.h
+++ b/gegl/gegl-chant.h
@@ -28,6 +28,7 @@
 
 #include <gegl-plugin.h>
 
+G_BEGIN_DECLS
 
 GType gegl_chant_get_type (void);
 typedef struct _GeglChantO  GeglChantO;
@@ -846,4 +847,5 @@ gegl_chant_init_properties (GeglChant *self)
   self->properties = g_slice_new0 (GeglChantO);
 }
 
+G_END_DECLS
 /****************************************************************************/
diff --git a/gegl/gegl-plugin.h b/gegl/gegl-plugin.h
index cad2b73..c9aae48 100644
--- a/gegl/gegl-plugin.h
+++ b/gegl/gegl-plugin.h
@@ -28,6 +28,8 @@
 #include <glib-object.h>
 #include <gegl.h>
 
+G_BEGIN_DECLS
+
 /* Extra types needed when coding operations */
 typedef struct _GeglOperation        GeglOperation;
 typedef struct _GeglOperationContext GeglOperationContext;
@@ -150,4 +152,5 @@ typedef struct
 
 #include <gegl-lookup.h>
 
+G_END_DECLS
 #endif  /* __GEGL_PLUGIN_H__ */