Add the conceal patch from Vince Negri.
diff --git a/src/globals.h b/src/globals.h
index b085bcb..f4ec257 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -1151,6 +1151,9 @@
EXTERN int lcs_tab1 INIT(= NUL);
EXTERN int lcs_tab2 INIT(= NUL);
EXTERN int lcs_trail INIT(= NUL);
+#ifdef FEAT_CONCEAL
+EXTERN int lcs_conceal INIT(= '-');
+#endif
#if defined(FEAT_WINDOWS) || defined(FEAT_WILDMENU) || defined(FEAT_STL_OPT) \
|| defined(FEAT_FOLDING)
@@ -1412,7 +1415,7 @@
#endif
EXTERN char_u e_invrange[] INIT(= N_("E16: Invalid range"));
EXTERN char_u e_invcmd[] INIT(= N_("E476: Invalid command"));
-#if defined(UNIX) || defined(FEAT_SYN_HL)
+#if defined(UNIX) || defined(FEAT_SYN_HL) || defined(FEAT_SPELL)
EXTERN char_u e_isadir2[] INIT(= N_("E17: \"%s\" is a directory"));
#endif
#ifdef FEAT_LIBCALL