improve cmake version detection

[wfurt]

I was trying to build runtime on Centos7 and use available cmake3-3.14.7-1.el7.x86_64 package. That should be sufficient to build but the build complained about old version.

[root@cent runtime]# cmake --version
cmake3 version 3.14.7

CMake suite maintained and supported by Kitware (kitware.com/cmake).

this is because version is prefixed with cmake3 instead of cmake

[ghost]

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[jkotas]

cc @am11

[janvorli]

LGTM, thank you!