[ltp] [T40]Can't compile ibm-acpi on Slackware

[Rainarrow]

I just installed Slackware 10.2 on my T40 someday before, and now I am 
trying to install IBM-ACPI on it. I got the following error message while 
trying to "make"

--------     Here begins error msg    -----------

root@Raw's_Slack:~/ibm-acpi-0.11# make
make -C /lib/modules/2.4.31/build SUBDIRS=/root/ibm-acpi-0.11 modules
make[1]: Entering directory `/usr/src/linux-2.4.31'
make -C  /root/ibm-acpi-0.11 
CFLAGS="-D__KERNEL__ -I/usr/src/linux-2.4.31/include -Wall -Wstrict-prototypes 
 -Wno-trigraphs -O2 -fno-strict-aliasing -fno-common -fomit-frame-pointer -pipe 
 -mpreferred-stack-boundary=2 -march=i486  -DMODULE" MAKING_MODULES=1 
modules
make[2]: Entering directory `/root/ibm-acpi-0.11'
make[2]: *** No rule to make target `modules'.  Stop.
make[2]: Leaving directory `/root/ibm-acpi-0.11'
make[1]: *** [_mod_/root/ibm-acpi-0.11] Error 2
make[1]: Leaving directory `/usr/src/linux-2.4.31'
make: *** [default] Error 2
root@Raw's_Slack:~/ibm-acpi-0.11#

---------    Here ends error msg    ---------

I've done some Googling for this, and someone says it's because I have no 
Linux kernel source installed on my system. But I checked the /usr/src/linux 
2.4.31, it does exists, containing some directories such as etc, include, .

My Slackware is a fresh full install, with the bareacpi.i kernel, it's ver 
2.4.31.

The readme file for IBM-ACPI could found here:
http://ibm-acpi.sourceforge.net/README

and the following is what "installation" section of the readme file said:

-----------      Here begins reference to readme    ---------------

First, you need to get a kernel with ACPI support up and running.
Please refer to http://acpi.sourceforge.net/ for help with this
step. How successful you will be depends a lot on you ThinkPad model,
the kernel you are using and any additional patches applied. The
kernel provided with your distribution may not be good enough. I
needed to compile a 2.6.7 kernel with the 20040715 ACPI patch to get
ACPI working reliably on my ThinkPad X40. Old ThinkPad models may not
be supported at all.

Assuming you have the basic ACPI support working (e.g. you can see the
/proc/acpi directory), follow the following steps to install this
driver:

	- unpack the archive:

		tar xzvf ibm-acpi-x.y.tar.gz; cd ibm-acpi-x.y

	- compile the driver:

		make

	- install the module in your kernel modules directory:

		make install

	- load the module:

		modprobe ibm_acpi

After loading the module, check the "dmesg" output for any error messages.

-------------------  Here ends reference to the 
me     ---------------------


Now that I can't pass the compilation, I don't have a clue, could anyone 
offer some help?
Thanks in advance.