Remove unused arguments from np_datetime_strings (pandas-dev#18565)

Author: jbrockmendel

pandas/_libs/src/datetime.pxd

@@ -7,9 +7,6 @@ from cpython cimport PyUnicode_Check, PyUnicode_AsASCIIString
 cdef extern from "numpy/ndarrayobject.h":
     ctypedef int64_t npy_datetime
 
-cdef extern from "numpy/npy_common.h":
-    ctypedef unsigned char npy_bool
-
 cdef extern from "datetime/np_datetime.h":
     ctypedef enum PANDAS_DATETIMEUNIT:
         PANDAS_FR_Y
@@ -37,11 +34,9 @@ cdef extern from "datetime/np_datetime.h":
 
 
 cdef extern from "datetime/np_datetime_strings.h":
-    int parse_iso_8601_datetime(char *str, int len, PANDAS_DATETIMEUNIT unit,
+    int parse_iso_8601_datetime(char *str, int len,
                                 pandas_datetimestruct *out,
-                                int *out_local, int *out_tzoffset,
-                                PANDAS_DATETIMEUNIT *out_bestunit,
-                                npy_bool *out_special)
+                                int *out_local, int *out_tzoffset)
 
 cdef inline int _string_to_dts(object val, pandas_datetimestruct* dts,
                            int* out_local, int* out_tzoffset) except? -1:
@@ -62,11 +57,8 @@ cdef inline int _cstring_to_dts(char *val, int length,
                                 pandas_datetimestruct* dts,
                                 int* out_local, int* out_tzoffset) except? -1:
     cdef:
-        npy_bool special
-        PANDAS_DATETIMEUNIT out_bestunit
         int result
 
-    result = parse_iso_8601_datetime(val, length, PANDAS_FR_ns,
-                                     dts, out_local, out_tzoffset,
-                                     &out_bestunit, &special)
+    result = parse_iso_8601_datetime(val, length,
+                                     dts, out_local, out_tzoffset)
     return result