Remove skiplist.pxd (#30269)

Author: WillAyd

pandas/_libs/skiplist.pxd

@@ -22,9 +22,27 @@ from pandas._libs.algos import is_monotonic
 
 from pandas._libs.util cimport numeric
 
-from pandas._libs.skiplist cimport (
-    skiplist_t, skiplist_init, skiplist_destroy, skiplist_get, skiplist_insert,
-    skiplist_remove)
+cdef extern from "../src/skiplist.h":
+    ctypedef struct node_t:
+        node_t **next
+        int *width
+        double value
+        int is_nil
+        int levels
+        int ref_count
+
+    ctypedef struct skiplist_t:
+        node_t *head
+        node_t **tmp_chain
+        int *tmp_steps
+        int size
+        int maxlevels
+
+    skiplist_t* skiplist_init(int) nogil
+    void skiplist_destroy(skiplist_t*) nogil
+    double skiplist_get(skiplist_t*, int, int*) nogil
+    int skiplist_insert(skiplist_t*, double) nogil
+    int skiplist_remove(skiplist_t*, double) nogil
 
 cdef:
     float32_t MINfloat32 = np.NINF

pandas/_libs/window/aggregations.pyx

@@ -687,6 +687,7 @@ def srcpath(name=None, suffix=".pyx", subdir="src"):
         "pyxfile": "_libs/window/aggregations",
         "language": "c++",
         "suffix": ".cpp",
+        "depends": ["pandas/_libs/src/skiplist.h"],
     },
     "_libs.window.indexers": {"pyxfile": "_libs/window/indexers"},
     "_libs.writers": {"pyxfile": "_libs/writers"},