Fix the skin modifier crashing when building without Bullet.

source/blender/modifiers/CMakeLists.txt

@@ -133,6 +133,10 @@ if(WITH_MOD_OCEANSIM)
 	add_definitions(-DWITH_OCEANSIM)
 endif()
 
+if(WITH_BULLET)
+	add_definitions(-DWITH_BULLET)
+endif()
+
 if(WITH_INTERNATIONAL)
 	add_definitions(-DWITH_INTERNATIONAL)
 endif()

source/blender/modifiers/SConscript

@@ -64,6 +64,9 @@ if env['WITH_BF_FLUID']:
 if env['WITH_BF_OCEANSIM']:
     defs.append('WITH_OCEANSIM')
 
+if env['WITH_BF_BULLET']:
+    defs.append('WITH_BULLET')
+
 if env['WITH_BF_GAMEENGINE']:
     incs.append('#/extern/recastnavigation')
     defs.append('WITH_GAMEENGINE')

source/blender/modifiers/intern/MOD_skin.c

@@ -218,6 +218,7 @@ static bool skin_frame_find_contained_faces(const Frame *frame,
 /* Returns true if hull is successfully built, false otherwise */
 static bool build_hull(SkinOutput *so, Frame **frames, int totframe)
 {
+#ifdef WITH_BULLET
 	BMesh *bm = so->bm;
 	BMOperator op;
 	BMIter iter;
@@ -326,6 +327,9 @@ static bool build_hull(SkinOutput *so, Frame **frames, int totframe)
 	BM_mesh_delete_hflag_tagged(bm, BM_ELEM_TAG, BM_EDGE | BM_FACE);
 
 	return true;
+#else
+	return false;
+#endif
 }
 
 /* Returns the average frame side length (frames are rectangular, so