* Consistently use "/usr/src" as download and staging area
* install-cmake-binary: Introduce CMAKE_ROOT var
* build-and-install-openssl: Remove redundant -fPIC flag, download openssl sources using "wget"
Older versions of git included in older linux distributions are not able
to download source from Github. A newer version is required with a newer
OpenSSL. This requires to also build curl with the same OpenSSL.
CMake is downloaded precompiled if available (64bits system) or compiled
from source otherwise.