How can I activate c ++ 11 in my version of GCC (7.3.0) to install CMake?

I am trying to install cmake in my Dell Inspiron 15 500, but when a run the command

./bootstrap

I get

---

CMake 3.12.2, Copyright 2000-2018 Kitware, Inc. and Contributors

C compiler on this system is: cc

Error when bootstrapping CMake: Cannot find a C++ compiler that supports both C++11 and the specified C++ flags. Please specify one using environment variable CXX. The C++ flags are "". They can be changed using the environment variable CXXFLAGS.

See cmake_bootstrap.log for compilers attempted.

Log of errors: /home/jogabell/Descargas/cmake-3.12.2/Bootstrap.cmk/cmake_bootstrap.log

How can I activate c ++ 11 in my version of GCC (7.3.0) to install CMake?