Add missing source file from previous patch

Huks.

unix/ppoll.c

@@ -0,0 +1,35 @@
+/*  ppoll.c -- MiNTLib.
+    Copyright (C) 2024 Thorsten Otto
+
+    This file is part of the MiNTLib project, and may only be used
+    modified and distributed under the terms of the MiNTLib project
+    license, COPYMINT.	By continuing to use, modify, or distribute
+    this file you indicate that you have read the license and
+    understand and accept it fully.
+*/
+
+#include <signal.h>
+#include <sys/select.h>
+#include <sys/poll.h>
+#include <sys/time.h>
+
+__typeof__(ppoll) __ppoll;
+
+int
+__ppoll (struct pollfd *fds, nfds_t nfds, const struct timespec *tmo, const sigset_t *sigmask)
+{
+	sigset_t savemask;
+	int retval;
+	__int32_t timeout = tmo == NULL ? -1 : tmo->tv_sec * 1000 + (tmo->tv_nsec + 999999) / 1000000;
+
+  /* The setting and restoring of the signal mask and the select call
+     should be an atomic operation.  This can't be done without kernel
+     help.  */
+	if (sigmask != NULL)
+		__sigprocmask(SIG_SETMASK, sigmask, &savemask);
+	retval = poll(fds, nfds, timeout);
+	if (sigmask != NULL)
+		__sigprocmask(SIG_SETMASK, &savemask, NULL);
+	return retval;
+}
+weak_alias (__ppoll, ppoll)