CMAKE and cross compiling - cmake

Question

I have to change sysroot for my cmake. There is rootfs located on my disk in /u02/rootfs.
I created toolchain_rootfs file and added this config into it:
SET(CMAKE_INSTALL_PREFIX "/u02/rootfs")
set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSROOT ${CMAKE_INSTALL_PREFIX})
#set(CMAKE_STAGING_PREFIX /home/devel/stage)
set(CMAKE_FIND_ROOT_PATH ${CMAKE_INSTALL_PREFIX})
set(CMAKE_C_COMPILER "${CMAKE_INSTALL_PREFIX}/usr/bin/gcc")
set(CMAKE_CXX_COMPILER "${CMAKE_INSTALL_PREFIX}/usr/bin/c++")
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
###
SET(CMAKE_SKIP_BUILD_RPATH FALSE)
SET(CMAKE_BUILD_WITH_INSTALL_RPATH TRUE)
SET(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/usr/lib")
SET(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/usr/lib")
After that I run cmake with option:
cmake ../myproject/ -DCMAKE_TOOLCHAIN_FILE=/u02/myproject/toolchain_rootfs
And got error like this:
------------ /u02/rootfs/usr/lib
------------ /u02/rootfs/usr/lib
-- The C compiler identification is unknown
-- The CXX compiler identification is GNU 5.4.0
-- Check for working C compiler: /u02/rootfs/usr/bin/gcc
------------ /u02/rootfs/usr/lib
-- Check for working C compiler: /u02/rootfs/usr/bin/gcc -- broken
CMake Error at /usr/share/cmake-3.5/Modules/CMakeTestCCompiler.cmake:61 (message):
The C compiler "/u02/rootfs/usr/bin/gcc" is not able to
compile a simple test program.
It fails with the following output:
Change Dir: /u02/myproject/CMakeFiles/CMakeTmp
Run Build Command:"/usr/bin/make" "cmTC_0e039/fast"
/usr/bin/make -f CMakeFiles/cmTC_0e039.dir/build.make
CMakeFiles/cmTC_0e039.dir/build
make[1]: Entering directory '/u02/myproject_build/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_0e039.dir/testCCompiler.c.o
/u02/rootfs/usr/bin/gcc -o
CMakeFiles/cmTC_0e039.dir/testCCompiler.c.o -c
/u02/myproject_build/CMakeFiles/CMakeTmp/testCCompiler.c
/u02/rootfs/usr/bin/../lib/gcc/x86_64-linux-gnu/4.9/cc1:
error while loading shared libraries: libisl.so.10: cannot open shared
object file: No such file or directory
Could you help me please solve this error. I went through cmake manual, set RPATH, but it doesn't work to me. What is wrong?
UDP1:
I've tried to use sysroot, without toolchain like:
SET(CMAKE_INSTALL_PREFIX "/u02/rootfs")
set(CMAKE_SYSROOT ${CMAKE_INSTALL_PREFIX})
set(CMAKE_FIND_ROOT_PATH ${CMAKE_INSTALL_PREFIX})
SET(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/usr/lib/x86_64-linux-gnu")
CMAKE was passed, but MAKE was failed. I got error:
/u02/rootfs/usr/bin/ar: error while loading shared libraries: libbfd-2.25-system.so: cannot open shared object file: No such file or directory
rootfs has this library.
How to specify PATH to LIBs in rootfs(sysroot)?