ltmodem & installation kernel source

[Mohsen Pahlevanzadeh <mohsen@pahlevanzadeh.org>]

Dear all,

I wanna to install ltmodem,But i must install linux source & linux
headers at first.

When i use uname -a i see 686 in output.

When i use ./configure for source of ltmodem,I see following outputs:

Checking for kernel headers
  ... in /usr/src/linux: nope
  ... in /usr/src/kernel-headers-2.6.18-4-686: nope
  ... in /usr/src/linux-2.6.18: nope
  ... in /usr/src/linux-2.6.18-4-686: nope
  ... in /lib/modules/2.6.18-4-686/build: Kernel headers found in
/lib/modules/2.6.18-4-686/build
  using /lib/modules/2.6.18-4-686/build
However, when i use ls command in /usr/src , i see following output:

debian:/usr/src# ls
kernel-patches          linux-headers-2.6.18-4-686  linux-source-2.6.18
linux-headers-2.6.18-4  linux-kbuild-2.6.18        
linux-source-2.6.18.tar.bz2
debian:/usr/src#
Because i installed related packages.

Please help me that i what i do with those directories.

Yours,Mohsen