What is GCC lto wrapper?

I am using buildroot to prepare images for embedded system. I want to export buildroots internal cross compiler so others can use same version, After command checking GCC version: arm-linux-gcc -vI see configured COLLECT_LTO_WRAPPER to static location on my HDD

 COLLECT_LTO_WRAPPER=/home/user/arm/buildroot/output/host/usr/libexec/gcc/arm-unknown-linux-uclibcgnueabi/4.7.1/lto-wrapper

It will not be correct on another system.

I was only able to find that LTO means Link Time Optimization. Can you please explain what is lto wrapper used for and when is needed?