[CMake] CheckIncludeFiles problem

[Yngve Inntjore Levinsen]

Dear all,

I have a problem with CheckIncludeFiles that I cannot figure out. I'm sure I'm 
just making a stupid mistake though, but I am unable to figure out what. The 
following code is in CMakeLists.txt:

include(CheckIncludeFiles)

check_include_files("readline/history.h" HAVE_READLINE_HISTORY_H)
check_include_files("sys/select.h" HAVE_SYS_SELECT_H)


And both headers are installed on my system:
$ ls -lh /usr/include/sys/select.h /usr/include/readline/history.h
-rw-r--r-- 1 root root 9,9K 21.07.2011 04:40 /usr/include/readline/history.h
-rw-r--r-- 1 root root 4,1K 26.10.2011 20:03 /usr/include/sys/select.h

CMake only finds sys/select.h though, and I don't see the difference. What might 
I be missing? I use cmake version 2.8.7.

Thanks!

Cheers,
Yngve