[gnumeric] Fix warning due to missing include.

[Morten Welinder <mortenw src gnome org>]

commit c191a2de5cd5abb31cce124f6119ee50915eda68
Author: Morten Welinder <terra gnome org>
Date:   Fri Apr 17 13:04:00 2009 -0400

    Fix warning due to missing include.
---
 src/gnumeric-gconf.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/src/gnumeric-gconf.c b/src/gnumeric-gconf.c
index f032135..ec78117 100644
--- a/src/gnumeric-gconf.c
+++ b/src/gnumeric-gconf.c
@@ -38,6 +38,7 @@
 #include <value.h>
 #include <number-match.h>
 #include <string.h>
+#include <sheet.h>
 
 static GnmAppPrefs prefs;
 GnmAppPrefs const *gnm_app_prefs = &prefs;