diff -Nur a/sh_util/gpshare.c b/sh_util/gpshare.c
--- a/sh_util/gpshare.c	2016-11-13 00:53:39.000000000 +0100
+++ b/sh_util/gpshare.c	2020-06-22 20:24:08.160203885 +0200
@@ -28,7 +28,7 @@
 
 static int gIsAtty1 = 1, gIsAtty2 = 1;
 extern int gLoadedBm, gBookmarkMatchMode;
-Bookmark gBm;
+extern Bookmark gBm;
 
 double
 FileSize(double size, const char **uStr0, double *uMult0)
