put box2d cmakelist to external

external/Box2D/CMakeLists.txt

@@ -1,62 +0,0 @@
-set(BOX2D_SRC
-  Collision/Shapes/b2ChainShape.cpp
-  Collision/Shapes/b2CircleShape.cpp
-  Collision/Shapes/b2EdgeShape.cpp
-  Collision/Shapes/b2PolygonShape.cpp
-  Collision/b2BroadPhase.cpp
-  Collision/b2CollideCircle.cpp
-  Collision/b2CollideEdge.cpp
-  Collision/b2CollidePolygon.cpp
-  Collision/b2Collision.cpp
-  Collision/b2Distance.cpp
-  Collision/b2DynamicTree.cpp
-  Collision/b2TimeOfImpact.cpp
-  Common/b2BlockAllocator.cpp
-  Common/b2Draw.cpp
-  Common/b2Math.cpp
-  Common/b2Settings.cpp
-  Common/b2StackAllocator.cpp
-  Common/b2Timer.cpp
-  Dynamics/Contacts/b2ChainAndCircleContact.cpp
-  Dynamics/Contacts/b2ChainAndPolygonContact.cpp
-  Dynamics/Contacts/b2CircleContact.cpp
-  Dynamics/Contacts/b2Contact.cpp
-  Dynamics/Contacts/b2ContactSolver.cpp
-  Dynamics/Contacts/b2EdgeAndCircleContact.cpp
-  Dynamics/Contacts/b2EdgeAndPolygonContact.cpp
-  Dynamics/Contacts/b2PolygonAndCircleContact.cpp
-  Dynamics/Contacts/b2PolygonContact.cpp
-  Dynamics/Joints/b2DistanceJoint.cpp
-  Dynamics/Joints/b2FrictionJoint.cpp
-  Dynamics/Joints/b2GearJoint.cpp
-  Dynamics/Joints/b2Joint.cpp
-  Dynamics/Joints/b2MouseJoint.cpp
-  Dynamics/Joints/b2MotorJoint.cpp
-  Dynamics/Joints/b2PrismaticJoint.cpp
-  Dynamics/Joints/b2PulleyJoint.cpp
-  Dynamics/Joints/b2RevoluteJoint.cpp
-  Dynamics/Joints/b2RopeJoint.cpp
-  Dynamics/Joints/b2WeldJoint.cpp
-  Dynamics/Joints/b2WheelJoint.cpp
-  Dynamics/b2Body.cpp
-  Dynamics/b2ContactManager.cpp
-  Dynamics/b2Fixture.cpp
-  Dynamics/b2Island.cpp
-  Dynamics/b2World.cpp
-  Dynamics/b2WorldCallbacks.cpp
-  Rope/b2Rope.cpp
-)
-
-include_directories(
-  ..
-)
-
-add_library(box2d STATIC
-  ${BOX2D_SRC}
-)
-
-set_target_properties(box2d
-    PROPERTIES
-    ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/lib"
-    LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/lib"
-)