shells/zsh: fix WANTLIB

Fix WANTLIB (missing util).

Found by using dpb -R (it didn't rebuild zsh after the recent bumps
to libutil, which then caused build errors in other ports like
lang/bacon depending on zsh).

ok?

Ciao,
Kili

Index: Makefile
===================================================================
RCS file: /cvs/ports/shells/zsh/Makefile,v
diff -u -p -r1.98 Makefile
--- Makefile 8 Jan 2024 10:33:09 -0000 1.98
+++ Makefile 18 Dec 2024 05:49:41 -0000
@@ -1,7 +1,7 @@
COMMENT= Z shell, Bourne shell-compatible

V= 5.9
-REVISION= 0
+REVISION= 1
DISTNAME= zsh-$V
CATEGORIES= shells

@@ -17,7 +17,7 @@ EXTRACT_SUFX= .tar.xz
# BSD
PERMIT_PACKAGE= Yes

-WANTLIB= c curses iconv m pcre
+WANTLIB= c curses iconv m pcre util

LIB_DEPENDS= converters/libiconv \
devel/pcre