It is automatically set in CMakeFindBinUtils.cmake using the value
of _CMAKE_TOOLCHAIN_PREFIX extracted from the compiler name within
CMakeDetermineCCompiler.cmake.
The CMake issue is #15448 - https://cmake.org/Bug/view.php?id=15448
This commit updates the toolchain to ensure libraries associated with arm
can be found. While a new root path needed to be set for armv6, the
most recent armv7 toolchain doesn't require to explicitly set a new
root.