libmcrypt currently has no maintainer.

There is no new libmcrypt version since February 2007.

http://sourceforge.net/project/showfiles.php?group_id=87941

Are you sure that libmcrypt itself depends on libtool or just the php module? The last one has libtool as optdepends.

I'm not sure, the only thing I've tested was the php module I wanted to use. But I've just seen few minutes ago the libmcrypt PKGBUILD, and I think its outdated:

# $Id$
# Maintainer: Jan de Groot <jgc@archlinux.org>
# Contributor: Tom Newsom <Jeepster@gmx.co.uk>

pkgname=libmcrypt
pkgver=2.5.8
pkgrel=1
pkgdesc="A library which provides a uniform interface to several symmetric encryption algorithms"
arch=(i686 x86_64)
license=('LGPL')
depends=('glibc')
options=('!libtool')
source=(http://downloads.sourceforge.net/mcrypt/${pkgname}-${pkgver}.tar.bz2)
url="http://mcrypt.sourceforge.net/"
md5sums=('c4f491dd411a09e9de3b8702ea6f73eb')

build() {
cd ${startdir}/src/${pkgname}-${pkgver}
./configure --prefix=/usr
make || return 1
make DESTDIR=${startdir}/pkg install
}

I don't know what variable "options" means(deprecated?), it isn't at ArchWiki's page about PKGBUILDs, also I don't trust on "!" that goes before libtool, it seems to avoid use libtool pkg? I'm new with this, but I think you should replace "options=('!libtool')" line with optdepends=('libtool: for make php module work properly') or something like that. I repeat: I have only tested it with php, so I don't know if it works properly when you don't use php module.

Sorry about my english, I have to learn a bit more.

options=(!libtool) is valid. Please see `man PKGBUILD` for details

Unless you know if libs don't work without libtool, you should add:
optdepends=('libtool: for make php module work properly')

I don't see any bug here. libmcrypt itself does not depend on libtool (I checked with namcap, ldd and plain strings command). The mcrypt module of php need libmcrypt and libtool. But this is already coverd by optdepends in php.

And I am sorry, but adding libtool as optdepend to libmcrypt is quite insane.

OK, I'm a damn noob. I don't know how i installed php, but I don't remember having seen optdepends messages, also i thought they were written to pacman.log, but now i'm looking at it and don't.

Excuse me guys, it's my fault, i thought that dependency would came with libmcrypt, but it is already with php, as you say Pierre. i'm going to request a close.

By the way, I'm not sure if this is correct, in php's PKGBUILD:
optdepends=(
'mcrypt: mcrypt' \
'libtool: mcrypt' \

i think it's not necessary to install mcrypt, with libmcrypt it's enough.