Inline _Py_RestoreSignals() from CPython (#604)

private _Py_RestoreSignals() has been moved to CPython internals as of Python 3.13
See: python/cpython#106400
Its implementation has been the same in all supported by uvloop Pythons
(3.8+), so the inlining was not conditionalized.

uvloop/includes/compat.h

@@ -1,5 +1,6 @@
 #include <errno.h>
 #include <stddef.h>
+#include <signal.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 #include "Python.h"
@@ -83,3 +84,22 @@ int Context_Exit(PyObject *ctx) {
 }
 
 #endif
+
+/* inlined from cpython/Modules/signalmodule.c
+ * https://github.com/python/cpython/blob/v3.13.0a6/Modules/signalmodule.c#L1931-L1951
+ * private _Py_RestoreSignals has been moved to CPython internals in Python 3.13
+ * https://github.com/python/cpython/pull/106400 */
+
+void
+_Py_RestoreSignals(void)
+{
+#ifdef SIGPIPE
+    PyOS_setsig(SIGPIPE, SIG_DFL);
+#endif
+#ifdef SIGXFZ
+    PyOS_setsig(SIGXFZ, SIG_DFL);
+#endif
+#ifdef SIGXFSZ
+    PyOS_setsig(SIGXFSZ, SIG_DFL);
+#endif
+}

uvloop/includes/python.pxd

@@ -11,8 +11,6 @@ cdef extern from "Python.h":
     object PyUnicode_EncodeFSDefault(object)
     void PyErr_SetInterrupt() nogil
 
-    void _Py_RestoreSignals()
-
     object PyMemoryView_FromMemory(char *mem, ssize_t size, int flags)
     object PyMemoryView_FromObject(object obj)
     int PyMemoryView_Check(object obj)
@@ -29,3 +27,5 @@ cdef extern from "includes/compat.h":
     void PyOS_BeforeFork()
     void PyOS_AfterFork_Parent()
     void PyOS_AfterFork_Child()
+
+    void _Py_RestoreSignals()