Merge branch 'wip/smcv/g-steal-fd-old-glib' into 'master'

backports: Avoid warnings for g_steal_fd when targeting older GLib

See merge request GNOME/libglnx!56

glnx-backports.h

@@ -125,16 +125,22 @@ _glnx_memdup2 (gconstpointer mem,
   (((a) > (b) ? (a) - (b) : (b) - (a)) < (epsilon))
 #endif
 
-#if !GLIB_CHECK_VERSION(2, 70, 0)
-#define g_steal_fd _glnx_steal_fd
 static inline int
 _glnx_steal_fd (int *fdp)
 {
+#if GLIB_CHECK_VERSION(2, 70, 0)
+  /* Allow it to be used without deprecation warnings, even if the target
+   * GLib version is older */
+  G_GNUC_BEGIN_IGNORE_DEPRECATIONS
+  return g_steal_fd (fdp);
+  G_GNUC_END_IGNORE_DEPRECATIONS
+#else
   int fd = *fdp;
   *fdp = -1;
   return fd;
-}
 #endif
+}
+#define g_steal_fd _glnx_steal_fd
 
 #if !GLIB_CHECK_VERSION(2, 74, 0)
 #define G_APPLICATION_DEFAULT_FLAGS ((GApplicationFlags) 0)