cmake: set CMP0074 to NEW (for OPENSSL_ROOT in appveyor) We have $env:OPENSSL_ROOT (env) equals to -DOPENSSL_ROOT (cmake variable) anyway. cmake complains: Policy CMP0074 is not set: find_package uses <PackageName>_ROOT variables. Run "cmake --help-policy CMP0074" for policy details. Use the cmake_policy command to set the policy and suppress this warning. Environment variable OpenSSL_ROOT is set to: C:/OpenSSL-Win64/bin For compatibility, CMake is ignoring the variable. This warning is for project developers. Use -Wno-dev to suppress it.