Linux: it asks cmake >= 2.8 however 2.8 installed

[Zenitur]

$ cd nheqminer-0.5c/
$ ls
3rdparty  CMakeLists.txt  cpu_xenoncat  cuda_tromp   nheqminer
blake2    cpu_tromp       cuda_djezo    LICENSE_MIT  README.md
$ cd cuda_tromp/
$ ls
blake2b.cu      cuda_tromp.cpp  cuda_tromp.vcxproj  equi_miner.cu
CMakeLists.txt  cuda_tromp.hpp  eqcuda.hpp
$ mkdir build && cd build
$ cmake ..
-- The C compiler identification is GNU 4.7.4
-- The CXX compiler identification is GNU 4.7.4
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Found CUDA: /usr/local/cuda (found version "7.5")
-- Looking for include file pthread.h
-- Looking for include file pthread.h - found
-- Looking for pthread_create
-- Looking for pthread_create - not found
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - found
-- Found Threads: TRUE
-- Boost version: 1.58.0
-- Found the following Boost libraries:
--   system
--   log_setup
--   log
--   date_time
--   filesystem
--   thread
CUDA FOUND
-- CUDA_NVCC_FLAGS: -gencode;arch=compute_20,code=sm_21;-gencode;arch=compute_30,code=sm_30;-gencode;arch=compute_35,code=sm_35;-gencode;arch=compute_50,code=sm_50;-gencode;arch=compute_52,code=sm_52;-gencode;arch=compute_61,code=sm_61
CMake Warning (dev) in CMakeLists.txt:
  No cmake_minimum_required command is present.  A line of code such as

    cmake_minimum_required(VERSION 2.8)

  should be added at the top of the file.  The version specified may be lower
  if you wish to support older CMake versions for this project.  For more
  information run "cmake --help-policy CMP0000".
This warning is for project developers.  Use -Wno-dev to suppress it.

-- Configuring done
-- Generating done
-- Build files have been written to: /home/zenitur/nheqminer-0.5c/cuda_tromp/build
$ cmake --version
cmake version 2.8.12.2
$