Package dependency problem with scilab and pkg-config

There is a package dependency problem for Scilab and pkg-config.

$ sudo apt-get install scilab -qq

then

$ pkg-config scilab --cflags-only-I
Package libxml-2.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `libxml-2.0.pc'
to the PKG_CONFIG_PATH environment variable
Package 'libxml-2.0', required by 'libscilab', not found

The libxml2-dev package contains the 'libxml-2.0.pc' file mentioned in the error message.
Installing the appropriate package fixes the problem:

$ sudo apt-get install libxml2-dev -qq
$ pkg-config scilab --cflags-only-I
-I/usr/include/libxml2 -I/usr/include/scilab

More info about scilab:

$ apt-cache policy scilab
scilab:
  Installed: 5.5.0-2
  Candidate: 5.5.0-2
  Version table:
 *** 5.5.0-2 0
        500 http://gb.archive.ubuntu.com/ubuntu/ trusty/universe i386 Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: pkg-config 0.26-1ubuntu4
ProcVersionSignature: Ubuntu 3.13.0-34.60-generic 3.13.11.4
Uname: Linux 3.13.0-34-generic i686
ApportVersion: 2.14.1-0ubuntu3.3
Architecture: i386
CurrentDesktop: Unity
Date: Tue Sep 2 07:53:28 2014
InstallationDate: Installed on 2014-08-16 (16 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release i386 (20140722.2)
SourcePackage: pkg-config
UpgradeStatus: No upgrade log present (probably fresh install)