FindBullet
Try to find the Bullet physics engine
This module defines the following variables
BULLET_FOUND - Was bullet found
BULLET_INCLUDE_DIRS - the Bullet include directories
BULLET_LIBRARIES - Link to this, by default it includes
                   all bullet components (Dynamics,
                   Collision, LinearMath, & SoftBody)
 This module accepts the following variables
BULLET_ROOT - Can be set to bullet install path or Windows build path
    © 2000–2019 Kitware, Inc. and Contributors
Licensed under the BSD 3-clause License.
    https://cmake.org/cmake/help/v3.5/module/FindBullet.html