sysprof-user-sampler: implement await for FDs

This allows us to not need libdex 0.9+ for use by the sampler.

src/libsysprof/sysprof-fd-private.h

@@ -0,0 +1,39 @@
+/* sysprof-fd-private.h
+ *
+ * Copyright 2024 Christian Hergert <chergert@redhat.com>
+ *
+ * This library is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of the
+ * License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+#pragma once
+
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+#define SYSPROF_TYPE_FD (sysprof_fd_get_type())
+
+typedef struct _SysprofFD SysprofFD;
+
+GType      sysprof_fd_get_type (void) G_GNUC_CONST;
+int        sysprof_fd_peek     (const SysprofFD *fd);
+int        sysprof_fd_steal    (SysprofFD       *fd);
+SysprofFD *sysprof_fd_dup      (const SysprofFD *fd);
+void       sysprof_fd_free     (SysprofFD       *fd);
+
+G_DEFINE_AUTOPTR_CLEANUP_FUNC (SysprofFD, sysprof_fd_free)
+
+G_END_DECLS