cmake: 
-- The C compiler identification is GNU 7.3.0
-- The CXX compiler identification is GNU 7.3.0
-- 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
-- Detecting C compile features
-- Detecting C compile features - 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
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Configuring done
-- Generating done
-- Build files have been written to: /out

make: 
-- Configuring done
-- Generating done
-- Build files have been written to: /out
Scanning dependencies of target main
make[2]: Warning: File '/in/main.c' has modification time 28757 s in the future
[ 50%] Building C object CMakeFiles/main.dir/main.c.o
[100%] Linking C executable main
make[2]: warning:  Clock skew detected.  Your build may be incomplete.
[100%] Built target main