Make tests and examples use glad

tests/cursor.c

@@ -30,6 +30,7 @@
 //
 //========================================================================
 
+#include <glad/glad.h>
 #include <GLFW/glfw3.h>
 
 #if defined(_MSC_VER)
@@ -237,6 +238,7 @@ int main(void)
     }
 
     glfwMakeContextCurrent(window);
+    gladLoadGLLoader((GLADloadproc) glfwGetProcAddress);
 
     glfwGetCursorPos(window, &cursor_x, &cursor_y);
     printf("Cursor position: %f %f\n", cursor_x, cursor_y);