Added note for Windows users to enable git symbolic links support.

On Ubuntu 18.04 the systems cmake package is at version 3.10 which
is too old.

Norihiro Watanabe authored 5 years ago and Tom Fischer committed 5 years ago

as titled

BUILD_TESTING is a CMake convention used widely.

6.2 is the minimum tested compiler by our CI (on envinf1).
6.5 is the default gcc 6 in Ubuntu 16.04 when using the ubuntu-toolchain-r/test PPA.

;-separated list of processes to build, e.g.:

cmake . -DOGS_BUILD_PROCESSES="HT;LIE"