Fixes the class to use HOST_OS and HOST_ARCH to set the cmake SYSTEM
variables. The HOST variables should be used instead of
TARGET_OS/TARGET_ARCH because we want to control how cmake compiles for
where the package is going to run (the host), not what it will be
generating output for (the target). The distinction is only really
relevant when building canadian cross recipes.
Also fix up the host OS detection to account for MinGW by setting
CMAKE_SYSTEM_NAME to "Windows". This eliminates the need for meta-mingw
to patch this in all the cmake recipes it builds.
Signed-off-by: Joshua Watt <JPEWhacker@gmail.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
