pkg-config in configure skim

I have already install scim , scim-table and scim-pinyin

robin@slackware:/tmp/skim-1.4.5$ ./configure
Checking for Python : /usr/bin/python
Checking for SCons : Use Bundled scons.
Checking for kde-config : kde-config was found
Checking for kde version : 3.5.7
Checking for the qt library : qt is in /usr/lib/qt
Checking for uic : uic was found as /usr/lib/qt/bin/uic
Checking for moc : moc was found as /usr/lib/qt/bin/moc
Checking for the qt includes : ok /usr/lib/qt/include/
Checking for the kde includes : ok /usr/include
Checking for scim >= 1.4.4 ... Not Found
Checking for scim-x11utils ... Not Found
scim >= 1.4.4 was not found (mandatory).
Perhaps you should add the directory containing "scim.pc"
to the PKG_CONF

robin@slackware:/tmp/skim-1.4.5$ $PKG_CONFIG_PATH
-sh: /usr/lib/pkgconfig/: is a directory

robin@slackware:/tmp/skim-1.4.5$ ls /usr/lib/pkgconfig/ | grep scim
scim-x11utils.pc
scim.pc

robin@slackware:/tmp/skim-1.4.5$ pkg-config --cflags scim
-I/usr/scim/include/scim-1.0

What's the problem?
I don't know how to solve this problem
Thanks!

Skim uses scons script to build. What I did last time for skim 1.4.5:

scons configure prefix=/usr
scons -j3
mkdir -p /usr/lib/pkgconfig
cp skim.pc /usr/lib/pkgconfig/
scons install DESTDIR=/your/dest
makepkg skim-1.4.5-i686-1xc.tgz
installpkg skim-1.4.5-i686-1xc.tgz

Thanks, I have solved the problem
But now I can not launch scim with kde start

Any errors? did you try to manually start skim?