[csmith-project/csmith] 52ed39: Specify that `csmith` is a C++14 program.

[Eric Eide <noreply@github.com>]

  Branch: refs/heads/master
  Home:   https://github.com/csmith-project/csmith
  Commit: 52ed397506fac405e18be6d35598e3b277125f1d
      https://github.com/csmith-project/csmith/commit/52ed397506fac405e18be6d35598e3b277125f1d
  Author: Eric Eide <eeide@cs.utah.edu>
  Date:   2019-09-15 (Sun, 15 Sep 2019)

  Changed paths:
    M src/CMakeLists.txt

  Log Message:
  -----------
  Specify that `csmith` is a C++14 program.

This commit updates the CMake-based build path only.

This commit leaves CXX_STANDARD_REQUIRED unset, which allows the C++
language standard requirement to "decay" as described in the CMake
documentation:
https://cmake.org/cmake/help/latest/prop_tgt/CXX_STANDARD.html

Allowing for "decay" is maybe a bad idea, but I'm not sure, so let it
decay for now.


  Commit: 900729af2f1f4cb01805181b2a03ea142647a51b
      https://github.com/csmith-project/csmith/commit/900729af2f1f4cb01805181b2a03ea142647a51b
  Author: Eric Eide <eeide@cs.utah.edu>
  Date:   2019-09-15 (Sun, 15 Sep 2019)

  Changed paths:
    M CMakeLists.txt
    M doc/CMakeLists.txt
    M runtime/CMakeLists.txt
    M scripts/CMakeLists.txt
    M src/CMakeLists.txt

  Log Message:
  -----------
  Increase the `cmake_minimum_required` version to 3.1.

File `src/CMakeLists.txt` sets the `CXX_STANDARD` property to specify
the C++ language standard for `csmith`.  That property was added in
CMake 3.1.0.  (CMake 3.1.0 was released in December 2014.)


Compare: https://github.com/csmith-project/csmith/compare/98a7216989f1...900729af2f1f