Change global to C header file.

src/globals.h

@@ -34,6 +34,8 @@
 #define SCREEN_WIDTH 800
 #define SCREEN_HEIGHT 600
 
+extern "C" {
 extern SDL_Window *window;
 extern GLuint program_id;
 extern GLuint matrix_id;
+}

src/main.cpp

@@ -28,7 +28,7 @@
 #include <GL/glew.h>
 #include <GL/gl.h>
 
-#include "globals.hpp"
+#include "globals.h"
 #include "shaders.hpp"
 #include "simulation.hpp"
 

src/simulation.cpp

@@ -29,7 +29,7 @@
 #include <glm/gtc/matrix_transform.hpp>
 #include <SDL2/SDL.h>
 
-#include "globals.hpp"
+#include "globals.h"
 #include "input.hpp"
 #include "camera.hpp"
 #include "cube.hpp"