[CMake] CMake 2.6.0 cross-compile: 1st time failed, 2nd time passed

[ning]

Hi List,

I am here trying to cross-compile a tiny demo project
with cmake 2.6.0.

When I ran cmake for the first time, link failed because
CMAKE_C_FLAGS was not used to compile cmTryCompileExec.
Then I modified nothing, but only ran cmake again.
CMAKE_C_FLAGS was used properly and link passed.

The project settings and logs are attached below.
Could you point out which part I have done wrong and
how to fix it.
Thanks in advance.

Best regards.
ning

=====project setting=====
-----dir structure-----
.
|-- CMakeLists.txt
|-- build/
|-- cross-tools.cmake
`-- tiny.c

-----tiny.c-----
#include <stdio.h>
int main()
{
    printf("tiny\n");
    return 0;
}

-----CMakeLists.txt-----
PROJECT(tiny C)
ADD_EXECUTABLE(tiny tiny.c)

-----cross-tools.cmake-----
# cross compile path variables
SET(TOOLS_PATH    "/tftpboot/x86-linux2")
SET(SYSROOT_PATH  "/tftpboot/sysroot")
# cross compiler tools
SET(CMAKE_SYSTEM_NAME Linux)
SET(CMAKE_C_FLAGS       "--sysroot=${SYSROOT_PATH} -mfloat-abi=softfp")
SET(CMAKE_C_COMPILER    "arm-wrs-linux-gnueabi-gcc")
# search path
SET(CMAKE_FIND_ROOT_PATH ${SYSROOT_PATH} ${TOOLS_PATH})
# search for programs/header/libs in target directories
SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM ONLY)
SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
=====project setting end=====

=====1st time=====
-----command line-----
$cd build
$rm -r *
$cmake -DCMAKE_TOOLCHAIN_FILE=../cross-tools.cmake ..

-----CMakeFiles/CMakeError.log-----
10: Linking C executable cmTryCompileExec
11: /usr/local/bin/cmake -E cmake_link_script
    CMakeFiles/cmTryCompileExec.dir/link.txt --verbose=1
12: /tftpboot/x86-linux2/bin/arm-wrs-linux-gnueabi-gcc
    -fPIC CMakeFiles/cmTryCompileExec.dir/testCCompiler.c.o
    -o cmTryCompileExec -rdynamic.
13: /tftpboot/x86-linux2/bin/ld:
    crt1.o: No such file: No such file or directory
=====1st time end=====

=====2nd time=====
-----command line-----
$cmake -DCMAKE_TOOLCHAIN_FILE=../cross-tools.cmake ..

-----CMakeFiles/CMakeOutput.log-----
53: Linking C executable cmTryCompileExec
54: /usr/local/bin/cmake -E cmake_link_script
    CMakeFiles/cmTryCompileExec.dir/link.txt --verbose=1
55: /tftpboot/x86-linux2/bin/arm-wrs-linux-gnueabi-gcc
    --sysroot=/tftpboot/sysroot -mfloat-abi=softfp    -fPIC
    CMakeFiles/cmTryCompileExec.dir/CMakeCCompilerABI.c.o
    -o cmTryCompileExec -rdynamic.
=====2nd time end=====