Process script mode eats 2 first bytes of input
When process substitution is used in shell, the 2 first bytes are ignored by cmake.
cmake -P <(echo "cmake_policy(VERSION 3.6)")
will produce following error:
CMake Error at /proc/self/fd/11:1 (ake_policy): Unknown CMake command "ake_policy".
The workaround is to add 2 spaces at the beginning of the input.