MAINT: Remove private CopyMode enum to private header

Author: seberg

numpy/core/include/numpy/ndarraytypes.h

@@ -449,12 +449,6 @@ typedef struct {
         int len;
 } PyArray_Dims;
 
-typedef enum {
-        NPY_COPY_IF_NEEDED = 0,
-        NPY_COPY_ALWAYS = 1,
-        NPY_COPY_NEVER = 2,
-} _PyArray_CopyMode;
-
 typedef struct {
         /*
          * Functions to cast to most other standard types

numpy/core/src/multiarray/conversion_utils.h

@@ -9,6 +9,12 @@ PyArray_IntpConverter(PyObject *obj, PyArray_Dims *seq);
 NPY_NO_EXPORT int
 PyArray_OptionalIntpConverter(PyObject *obj, PyArray_Dims *seq);
 
+typedef enum {
+    NPY_COPY_IF_NEEDED = 0,
+    NPY_COPY_ALWAYS = 1,
+    NPY_COPY_NEVER = 2,
+} _PyArray_CopyMode;
+
 NPY_NO_EXPORT int
 PyArray_CopyConverter(PyObject *obj, _PyArray_CopyMode *copyflag);