Add additional internal includes and a few more declarations with
proper types, to avoid implicit ints and implicit function
declarations.  This prepares for future compilers which do not accept
these historic C features by default.

Fix the signature of internal_data_init to be consistent with its
caller.

diff --git a/corrida/forms.c b/corrida/forms.c
index dc5073b56c278b4a..70193bbca16e832f 100755
--- a/corrida/forms.c
+++ b/corrida/forms.c
@@ -1,4 +1,5 @@
 #include "forms.h"
+#include "gui.h"
 
 GArray *observations_runs_list;
 GArray *meteors_list;
diff --git a/corrida/gui.h b/corrida/gui.h
index fbc9aca2be207bf2..dc6ef12c0d6c2053 100755
--- a/corrida/gui.h
+++ b/corrida/gui.h
@@ -271,4 +271,7 @@ void draw_arrow( GdkPixmap *pixmap,
 		 guint x1, guint y1, guint x2, guint y2,
 		 char *string );
 
+extern GtkWidget *main_window;
+extern GtkWidget *charts_window;
+
 #endif
diff --git a/corrida/gui_about.c b/corrida/gui_about.c
index 328435d296871284..e0fc9b52876e6214 100755
--- a/corrida/gui_about.c
+++ b/corrida/gui_about.c
@@ -4,7 +4,6 @@ void menubar_about_clicked_cb( GtkMenuItem *menuitem,
 			       gpointer user_data )
 
 {
-  extern *main_window;
   GtkWidget *dialog;
   GtkWidget *vbox;
   GtkWidget *image;
diff --git a/corrida/gui_callbacks.c b/corrida/gui_callbacks.c
index 4d06e4137b89addd..e4f42d09d632468e 100755
--- a/corrida/gui_callbacks.c
+++ b/corrida/gui_callbacks.c
@@ -1,4 +1,5 @@
 #include "gui.h"
+#include "gui_open_form.h"
 
 GtkCellRendererText *current_observations_runs_cell = NULL;
 GtkCellRendererText *current_meteors_cell = NULL;
@@ -763,7 +764,6 @@ gint chart_mouse_button_pressed_cb( GtkWidget      *widget,
 gint charts_accept_button_pressed_cb( GtkWidget      *widget,
 				      gpointer        data)
 {
-  extern *charts_window;
   extern gint edition_status;
   extern corrida_charts_meteor_record current_meteor;
   extern GtkWidget *meteor_position_entry[4];
diff --git a/corrida/internal_data.c b/corrida/internal_data.c
index d2c287704f4e5c74..ca7c14c8e98ac9ee 100755
--- a/corrida/internal_data.c
+++ b/corrida/internal_data.c
@@ -2,8 +2,7 @@
 
 static internal_data internal_data_container;
 
-void internal_data_init( int  *argc,
-			 char ***argv )
+void internal_data_init( void )
 {
   extern internal_data internal_data_container;
   gchar path[MAX_CORRIDA_PATH_STRLEN];
diff --git a/corrida/internal_data.h b/corrida/internal_data.h
index f2ff58332d535c04..587311120797c6d1 100755
--- a/corrida/internal_data.h
+++ b/corrida/internal_data.h
@@ -30,8 +30,7 @@ typedef struct _internal_data {
   gchar *charts_path;     /* directory with charts */
 } internal_data;
 
-void internal_data_init( int  *argc,
-			 char ***argv );
+void internal_data_init( void );
 
 void internal_data_set_edition_stat( gint edition_stat );
 gint internal_data_get_edition_stat( void );
diff --git a/corrida/misc.c b/corrida/misc.c
index cab8fbec1dd54e25..dc0eb9648527dc48 100755
--- a/corrida/misc.c
+++ b/corrida/misc.c
@@ -1,4 +1,5 @@
 #include "misc.h"
+#include "gui.h"
 
 /* corrida_init: init corrida services */
 void corrida_init( int  *argc,