Build fails because SDL2 is not found

[Stokestack]

Running CMake on the src directory produces this output (on Mac OS):

CMake Error at CMakeLists.txt:85 (find_package):
  By not providing "FindSDL2.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "SDL2", but
  CMake did not find one.

  Could not find a package configuration file provided by "SDL2" with any of
  the following names:

    SDL2Config.cmake
    sdl2-config.cmake

The instructions don't mention this; the only dependency mentioned is Triangle, which I've copied into the specified place.

[luoyun7123]

emmm，the provider believes that most people have SDL2 and opengl in their computers, if you don't have them, just install one ......

[Stokestack]

Ummm... nope.

[micwoj92]

Project should have all dependencies listed, what if I want to build it on a server without gui? Doubt I will have opengl and sdl2 there.

[albertotono]

Yes, please make sure you Install SDL2, if you are on Linux you can follow these steps:

(The "issue" is reported here)

[tanxianjun2016]

mac os , already install SDL2, cmake note:
/Library/Frameworks/SDL2.framework/Headers/SDL_opengles2.h:35:10: fatal error: 'GLES2/gl2platform.h' file not found
#include <GLES2/gl2platform.h>