BLD: fix missing Python.h includes

`Python.h` must be included before including and standard library
headers, if it's pulled in (which happens when you include numpy
headers). Otherwise we see build warnings like:

```
142/244] Compiling C object numpy/core/_multiarray_umath.cpython-311-x86_64-linux-gnu.so.p/src_multiarray_textreading_field_types.c.o
In file included from /opt/hostedtoolcache/Python/3.11.0/x64/include/python3.11/Python.h:86,
                 from ../numpy/core/include/numpy/npy_common.h:5,
                 from ../numpy/core/include/numpy/ndarraytypes.h:4,
                 from ../numpy/core/src/multiarray/textreading/field_types.h:9,
                 from ../numpy/core/src/multiarray/textreading/field_types.c:1:
/opt/hostedtoolcache/Python/3.11.0/x64/include/python3.11/cpython/pytime.h:208:60: warning: ‘struct timespec’ declared inside parameter list will not be visible outside of this definition or declaration
  208 | PyAPI_FUNC(int) _PyTime_FromTimespec(_PyTime_t *tp, struct timespec *ts);
      |                                                            ^~~~~~~~
/opt/hostedtoolcache/Python/3.11.0/x64/include/python3.11/cpython/pytime.h:213:56: warning: ‘struct timespec’ declared inside parameter list will not be visible outside of this definition or declaration
  213 | PyAPI_FUNC(int) _PyTime_AsTimespec(_PyTime_t t, struct timespec *ts);
      |                                                        ^~~~~~~~
/opt/hostedtoolcache/Python/3.11.0/x64/include/python3.11/cpython/pytime.h:217:63: warning: ‘struct timespec’ declared inside parameter list will not be visible outside of this definition or declaration
  217 | PyAPI_FUNC(void) _PyTime_AsTimespec_clamp(_PyTime_t t, struct timespec *ts);
      |                                                               ^~~~~~~~
```

numpy/core/src/multiarray/textreading/field_types.h

@@ -2,6 +2,9 @@
 #ifndef NUMPY_CORE_SRC_MULTIARRAY_TEXTREADING_FIELD_TYPES_H_
 #define NUMPY_CORE_SRC_MULTIARRAY_TEXTREADING_FIELD_TYPES_H_
 
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+
 #include <stdint.h>
 #include <stdbool.h>
 #define NPY_NO_DEPRECATED_API NPY_API_VERSION

numpy/core/src/multiarray/textreading/readtext.c

@@ -1,9 +1,9 @@
-#include <stdio.h>
-#include <stdbool.h>
-
 #define PY_SSIZE_T_CLEAN
 #include <Python.h>
 
+#include <stdio.h>
+#include <stdbool.h>
+
 #define NPY_NO_DEPRECATED_API NPY_API_VERSION
 #define _MULTIARRAYMODULE
 #include "numpy/arrayobject.h"

numpy/core/src/multiarray/textreading/stream_pyobject.c

@@ -4,11 +4,12 @@
  * single line of a file.
  */
 
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+
 #include <stdio.h>
 #include <stdlib.h>
 
-#define PY_SSIZE_T_CLEAN
-#include <Python.h>
 #define NPY_NO_DEPRECATED_API NPY_API_VERSION
 #define _MULTIARRAYMODULE
 #include "numpy/arrayobject.h"

numpy/linalg/lapack_lite/f2c.c

@@ -7,10 +7,14 @@
   it is available, and shipping a static library isn't portable.
 */
 
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+
 #include "f2c.h"
 
 

numpy/linalg/lapack_lite/f2c.h

@@ -7,6 +7,9 @@
 #ifndef F2C_INCLUDE
 #define F2C_INCLUDE
 
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+
 #include <math.h>
 #include "numpy/npy_common.h"
 #include "npy_cblas.h"