build_api.py changes to take ARMC5 into account when validating for offical target/release combination
build_api.py changes to take ARMC5 into account when validating for offical target/release combination

andcor02/mbed-os,mbedmicro/mbed,mbedmicro/mbed,kjbracey-arm/mbed,mbedmicro/mbed,andcor02/mbed-os,kjbracey-arm/mbed,andcor02/mbed-os,andcor02/mbed-os,andcor02/mbed-os,mbedmicro/mbed,kjbracey-arm/mbed,andcor02/mbed-os,mbedmicro/mbed,kjbracey-arm/mbed