在windows7上编译rtt遇到了arm-none-eabi-gcc的问题如何解决呢

最近在windows7上编译rtt，考虑到用cygwin上的git,svn同步代码方便，希望把scons编译方式也加到cygwin上，遇到了一个
sh: arm-none-eabi-gcc: command not found
的问题
具体步骤如下：
1 安装cygwin，选择full install(带有python)
2 安装scons (python setup.py install)
3 安装arm-2012.09-63-arm-none-eabi-i686-mingw32.tar.bz2 (tar -jxvf arm-2012.09-63-arm-none-eabi-i686-mingw32.tar.bz2)
4 将arm-2012.09-63-arm-none-eabi-i686-mingw32解压后的路径export到PATH里
在wh44b0下做scons提示如下
$ scons scons: Reading SConscript files ... /opt/CrossCompile/CodeSourcery/Sourcery_CodeBench_for_ARM_EABI/bin:/cygdrive/c/linux/rt-thread/tool/arm-2012.09/bin/:/home/dillon.min/bin:/cygdrive/c/software/jd-gui-0.3.5.windows:/usr/local/bin:/usr/bin:/cygdrive/c/Program Files (x86)/CodeSourcery/Sourcery_CodeBench_Lite_for_ARM_EABI/bin:/cygdrive/c/Windows/system32:/cygdrive/c/Windows:/cygdrive/c/Windows/System32/Wbem:/cygdrive/c/Windows/System32/WindowsPowerShell/v1.0:/cygdrive/c/Old-Pc-bak/d/share/android-sdk_r10-windows/tools:/cygdrive/c/Old-Pc-bak/d/software/java反编译:/cygdrive/c/Program Files/7-Zip:/cygdrive/c/Python25:/cygdrive/c/Python25/Scripts:/cygdrive/c/Program Files (x86)/Beyond Compare 3:/usr/lib/lapack scons: done reading SConscript files. scons: Building targets ... scons: building associated VariantDir targets: build arm-none-eabi-gcc -o build/application.o -c -mcpu=arm720t -D__FLASH_BUILD__ -O2 -Ibuild -I. -I/cygdrive/c/linux/rt-thread/rt-2457-git -I/cygdrive/c/linux/rt-thread/rt-2457-git/build -I/cygdrive/c/linux/rt-thread/rt-2457-git/include -I/cygdrive/c/linux/rt-thread/rt-2457-git/libcpu/arm/s3c44b0 -I/cygdrive/c/linux/rt-thread/rt-2457-git/libcpu/arm/common application.c sh: arm-none-eabi-gcc: command not found scons: *** [build/application.o] Error 127 scons: building terminated because of errors.
但是我手动执行
arm-none-eabi-gcc -o build/application.o -c -mcpu=arm720t -DFLASH_BUILD -O2 -Ibuild -I. -I/cygdrive/c/linux/rt-thread/rt-2457-git -I/cygdrive/c/linux/rt-thread/rt-2457-git/build -I/cygdrive/c/linux/rt-thread/rt-2457-git/include -I/cygdrive/c/linux/rt-thread/rt-2457-git/libcpu/arm/s3c44b0 -I/cygdrive/c/linux/rt-thread/rt-2457-git/libcpu/arm/common application.c
是可以把application.o生成到build下的

可能问题就出在scons里对arm-none-eabi-gcc查找上出了问题，在building.py里加了一个 print os.environ[‘PATH’]
说明gcc的工具是在路径里的，就比较迷惑了