git rev: master/3d2c0f5902cacf9d8544bf263b51ef0dd1a7218c

Steps:
1. Install ppc7400 sdk_ext in poky_sdk_ppc7400 directory and set the environment. Check the path for devtool and ${CC}: 

$ which devtool
/buildarea/poky_sdk_ppc7400/sysroots/x86_64-pokysdk-linux//usr/bin/devtool

$ which ${CC}
/buildarea/poky_sdk_ppc7400/tmp/sysroots/x86_64-linux/usr/bin/powerpc-poky-linux/powerpc-poky-linux-gcc

2. In same session, install i586 sdk_ext in poky_sdk_i586 directory and set the environment. Check the path for devtool and ${CC} again:

$ which devtool
/buildarea/poky_sdk_ppc7400/sysroots/x86_64-pokysdk-linux//usr/bin/devtool

$ which ${CC}
/buildarea/poky_sdk_i586/tmp/sysroots/x86_64-linux/usr/bin/i586-poky-linux/i586-poky-linux-gcc

The path for devtool still point to poky_sdk_ppc7400, not poky_sdk_i586.