CMake Error: CMake was unable to find a build program corresponding to “Unix Makefiles”. CMAKE_MAKE_PROGRAM is not set. You probably need to select a different build tool.
CMake Error: Error required internal CMake variable not set, cmake may be not be built correctly.
Missing variable is:
CMAKE_C_COMPILER_ENV_VAR
CMake Error: Error required internal CMake variable not set, cmake may be not be built correctly.
Missing variable is:
CMAKE_C_COMPILER

Fix: yum groups install “Development Tools”

If still error:
CMake Error at CMakeLists.txt:26 (project):
No CMAKE_CXX_COMPILER could be found.

or

Your C++ compiler supports C++11, compiling in that mode.
Downloading Clang 3.5
CMake Error at ycm/CMakeLists.txt:97 (message):

Fix. yum install gcc gcc-c++ clang