--- a/src/hexedit.h
+++ b/src/hexedit.h
@@ -340,7 +340,7 @@
 
 
    /* Global structure, keep most global variables here. */
-struct
+struct Globals_t
 {
    WINDOW *wmain, *wstatus, *whelp; /* three windows used throughout. */
    unsigned long filesize;          /* size of the file buffer. */
@@ -362,7 +362,9 @@
                                     /* buf end. */
    int beeping;                     /* Allow beeping or not. */
    int help_msg_count;              /* Number of messages in help menu. */
-} Globals;
+};
+
+extern struct Globals_t Globals;
 
 
 struct foundit
@@ -397,7 +399,9 @@
    int s;
    struct Change *base;
    struct Change *top;
-} UndoStack;
+};
+
+extern struct ChangeLog UndoStack;
 
 
 struct FileNames
--- a/src/main.c
+++ b/src/main.c
@@ -16,6 +16,7 @@
 #include "hexedit.h"
 #include <assert.h>
 
+struct Globals_t Globals;
 
 int
 main (int argc, char **argv)
--- a/src/undo.c
+++ b/src/undo.c
@@ -15,6 +15,7 @@
 #include <assert.h>
 #include "hexedit.h"
 
+struct ChangeLog UndoStack;
 
 void
 pushUndo (int type, unsigned long offset,