be a bit more blunt in the error message (merge from devbr6)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@37140 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/gis/gisinit.c

@@ -51,7 +51,8 @@ void G__gisinit(const char *version, const char *pgm)
     G_set_program_name(pgm);
 
     if (strcmp(version, GIS_H_VERSION) != 0)
-	G_fatal_error(_("Incompatible library version for module"));
+	G_fatal_error(_("Incompatible library version for module. "
+			"You need to rebuild GRASS or untangle multiple installations."));
 
     /* Make sure location and mapset are set */
     G_location_path();
@@ -85,7 +86,8 @@ void G__no_gisinit(const char *version)
 	return;
 
     if (strcmp(version, GIS_H_VERSION) != 0)
-	G_fatal_error(_("Incompatible library version for module"));
+	G_fatal_error(_("Incompatible library version for module. "
+			"You need to rebuild GRASS or untangle multiple installations."));
 
     gisinit();
 }