[libgda] GdaNumeric: Use the _ declaration technique.

[Murray Cumming <murrayc src gnome org>]

commit cd090c9069ace9680757930e445c821c0b86013a
Author: Murray Cumming <murrayc murrayc com>
Date:   Fri Nov 11 22:26:49 2011 +0100

    GdaNumeric: Use the _ declaration technique.
    
    This is what glib and GTK+ do. It allows the struct type to be
    pre-declared elsewhere, without including the header, and without
    causing a double declaration.

 libgda/gda-value.h |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)
---
diff --git a/libgda/gda-value.h b/libgda/gda-value.h
index 0098fdb..aeb2892 100644
--- a/libgda/gda-value.h
+++ b/libgda/gda-value.h
@@ -74,6 +74,9 @@ typedef struct {
 	gdouble y;
 } GdaGeometricPoint;
 
+
+typedef struct _GdaNumeric GdaNumeric;
+
 /**
  * GdaNumeric:
  * @number: a string representing a number
@@ -88,14 +91,14 @@ typedef struct {
  * Set value func: gda_value_set_numeric
  * Get value func: gda_value_get_numeric
  */
-typedef struct {
+struct _GdaNumeric {
 	gchar*   GSEAL(number);
 	glong    GSEAL(precision);
 	glong    GSEAL(width);
 	
 	/*< private >*/
 	gpointer reserved; /* reserved for future usage with GMP (http://gmplib.org/) */
-} GdaNumeric;
+};
 
 /**
  * GdaTime: