[easytag] Fix common symbol linker warnings

[David King <davidk src gnome org>]

commit 5709590dda8e909e5d0c85881aa1ced632d92e1b
Author: David King <amigadave amigadave com>
Date:   Thu Jan 8 20:02:01 2015 +0000

    Fix common symbol linker warnings
    
    Found with the --warn-common linker argument.

 src/easytag.c |    5 +++++
 src/easytag.h |    6 +++---
 src/setting.c |    2 ++
 src/setting.h |    2 +-
 4 files changed, 11 insertions(+), 4 deletions(-)
---
diff --git a/src/easytag.c b/src/easytag.c
index d48810e..81442eb 100644
--- a/src/easytag.c
+++ b/src/easytag.c
@@ -43,6 +43,11 @@
 
 static GtkWidget *QuitRecursionWindow = NULL;
 
+/* Referenced in the header. */
+gboolean Main_Stop_Button_Pressed;
+GtkWidget *MainWindow;
+gboolean ReadingDirectory;
+
 /* Used to force to hide the msgbox when saving tag */
 static gboolean SF_HideMsgbox_Write_Tag;
 /* To remember which button was pressed when saving tag */
diff --git a/src/easytag.h b/src/easytag.h
index 2047657..19c78f3 100644
--- a/src/easytag.h
+++ b/src/easytag.h
@@ -34,16 +34,16 @@
  ***************/
 
 /* Variable to force to quit recursive functions (reading dirs) or stop saving files */
-gboolean Main_Stop_Button_Pressed;
+extern gboolean Main_Stop_Button_Pressed;
 
-GtkWidget *MainWindow;
+extern GtkWidget *MainWindow;
 
 #ifndef errno
 extern int errno;
 #endif
 
 /* A flag to start/avoid a new reading while another one is running */
-gboolean ReadingDirectory;
+extern gboolean ReadingDirectory;
 
 
 /**************
diff --git a/src/setting.c b/src/setting.c
index 81943a5..e5d6e70 100644
--- a/src/setting.c
+++ b/src/setting.c
@@ -44,6 +44,8 @@
 
 #include "win32/win32dep.h"
 
+/* Referenced in the header. */
+GSettings *MainSettings;
 
 /***************
  * Declaration *
diff --git a/src/setting.h b/src/setting.h
index 5e31153..c6f8169 100644
--- a/src/setting.h
+++ b/src/setting.h
@@ -235,7 +235,7 @@ typedef enum
  * Config variables
  */
 
-GSettings *MainSettings;
+extern GSettings *MainSettings;
 
 void Init_Config_Variables (void);