Cleanup: Remove unnecessary "using" statements

intern/ghost/intern/GHOST_PathUtils.cc

@@ -18,7 +18,7 @@
 
 /* Based on: https://stackoverflow.com/a/2766963/432509 */
 
-using DecodeState_e = enum DecodeState_e {
+enum DecodeState_e {
   /** Searching for an ampersand to convert. */
   STATE_SEARCH = 0,
   /** Convert the two proceeding characters from hex. */

source/blender/blenkernel/BKE_editmesh_bvh.hh

@@ -19,8 +19,6 @@ struct BMVert;
 struct BMesh;
 struct BVHTree;
 
-using BMBVHTree = struct BMBVHTree;
-
 typedef bool (*BMBVHTree_FaceFilter)(struct BMFace *f, void *userdata);
 
 BMBVHTree *BKE_bmbvh_new_from_editmesh(struct BMEditMesh *em,

source/blender/blenlib/tests/BLI_polyfill_2d_test.cc

@@ -36,7 +36,7 @@ static void polyfill_to_obj(const char *id,
                             const uint tris[][3],
                             const uint tris_num);
 
-using ePolyFill2DTestFlag = enum ePolyFill2DTestFlag {
+enum ePolyFill2DTestFlag {
   POLYFILL2D_TEST_IS_DEGENERATE = (1 << 0),
   POLYFILL2D_TEST_NO_ZERO_AREA_TRIS = (1 << 1),
   POLYFILL2D_TEST_NOP = 0,

source/blender/blenlib/tests/BLI_task_test.cc

@@ -143,7 +143,7 @@ TEST(task, MempoolIter)
 
 /* *** Parallel iterations over mempool items with TLS. *** */
 
-using TaskMemPool_Chunk = struct TaskMemPool_Chunk {
+struct TaskMemPool_Chunk {
   ListBase *accumulate_items;
 };
 

source/blender/python/mathutils/mathutils.hh

@@ -89,8 +89,6 @@ PyMODINIT_FUNC PyInit_mathutils();
 int EXPP_FloatsAreEqual(float af, float bf, int maxDiff);
 int EXPP_VectorsAreEqual(const float *vecA, const float *vecB, int size, int floatSteps);
 
-using Mathutils_Callback = struct Mathutils_Callback;
-
 /** Checks the user is still valid. */
 using BaseMathCheckFunc = int (*)(BaseMathObject *);
 /** Gets the vector from the user. */

source/blender/windowmanager/intern/wm_event_system.cc

@@ -108,7 +108,7 @@ BLI_STATIC_ASSERT(sizeof(GHOST_TEventImeData) == sizeof(wmIMEData),
 /**
  * Return value of handler-operator call.
  */
-using eHandlerActionFlag = enum eHandlerActionFlag {
+enum eHandlerActionFlag {
   WM_HANDLER_BREAK = 1 << 0,
   WM_HANDLER_HANDLED = 1 << 1,
   /** `WM_HANDLER_MODAL | WM_HANDLER_BREAK` means unhandled. */