input: separate wakeup pipe creation into a separate function

Error handling is slightly reduced: we assume that setting a pipe
to non-blocking can never fail.

input/input.c

@@ -1492,20 +1492,9 @@ struct input_ctx *mp_input_init(struct mpv_global *global)
     }
 
 #ifndef __MINGW32__
-    int ret = pipe(ictx->wakeup_pipe);
-    if (ret == 0) {
-        for (int i = 0; i < 2 && ret >= 0; i++) {
-            mp_set_cloexec(ictx->wakeup_pipe[i]);
-            ret = fcntl(ictx->wakeup_pipe[i], F_GETFL);
-            if (ret < 0)
-                break;
-            ret = fcntl(ictx->wakeup_pipe[i], F_SETFL, ret | O_NONBLOCK);
-            if (ret < 0)
-                break;
-        }
-    }
+    int ret = mp_make_wakeup_pipe(ictx->wakeup_pipe);
     if (ret < 0)
-        MP_ERR(ictx, "Failed to initialize wakeup pipe: %s\n", strerror(errno));
+        MP_ERR(ictx, "Failed to initialize wakeup pipe: %s\n", strerror(-ret));
     else
         mp_input_add_fd(ictx, ictx->wakeup_pipe[0], true, NULL, read_wakeup,
                         NULL, NULL);

osdep/io.c

@@ -19,6 +19,7 @@
  */
 
 #include <unistd.h>
+#include <errno.h>
 
 #include "talloc.h"
 
@@ -41,6 +42,30 @@ bool mp_set_cloexec(int fd)
     return true;
 }
 
+#ifdef __MINGW32__
+int mp_make_wakeup_pipe(int pipes[2])
+{
+    pipes[0] = pipes[1] = -1;
+    return -ENOSYS;
+}
+#else
+// create a pipe, and set it to non-blocking (and also set FD_CLOEXEC)
+int mp_make_wakeup_pipe(int pipes[2])
+{
+    if (pipe(pipes) != 0) {
+        pipes[0] = pipes[1] = -1;
+        return -errno;
+    }
+
+    for (int i = 0; i < 2; i++) {
+        mp_set_cloexec(pipes[i]);
+        int val = fcntl(pipes[i], F_GETFL) | O_NONBLOCK;
+        fcntl(pipes[i], F_SETFL, val);
+    }
+    return 0;
+}
+#endif
+
 #ifdef _WIN32
 
 #include <windows.h>

osdep/io.h

@@ -44,6 +44,7 @@
 #endif
 
 bool mp_set_cloexec(int fd);
+int mp_make_wakeup_pipe(int pipes[2]);
 
 #ifdef _WIN32
 #include <wchar.h>