meson: update glib minimum version to 2.56

In order to support the symbol g_enum_to_string in various
project using GStreamer ( gst-validate etc.), the glib minimum
version should be 2.56.0.

Remove compat code as glib requirement
is now > 2.56

Version used by Ubuntu 18.04 LTS

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/874>

gst-libs/gst/video/video-anc.c

@@ -26,17 +26,6 @@
 #include <gst/base/gstbytereader.h>
 #include "video-anc.h"
 
-#if !GLIB_CHECK_VERSION(2, 47, 4)
-#ifdef __GNUC__
-#define G_GNUC_CHECK_VERSION(major, minor) \
-    ((__GNUC__ > (major)) || \
-     ((__GNUC__ == (major)) && \
-      (__GNUC_MINOR__ >= (minor))))
-#else
-#define G_GNUC_CHECK_VERSION(major, minor) 0
-#endif
-#endif
-
 /**
  * SECTION:gstvideoanc
  * @title: GstVideo Ancillary

gst-libs/gst/video/video-hdr.c

@@ -41,24 +41,6 @@
   (m)->max_display_mastering_luminance, \
   (m)->min_display_mastering_luminance
 
-/* g_ascii_string_to_unsigned is available since 2.54. Get rid of this wrapper
- * when we bump the version in 1.18 */
-#if !GLIB_CHECK_VERSION(2,54,0)
-#define g_ascii_string_to_unsigned video_hdr_ascii_string_to_unsigned
-static gboolean
-video_hdr_ascii_string_to_unsigned (const gchar * str, guint base, guint64 min,
-    guint64 max, guint64 * out_num, GError ** error)
-{
-  gchar *endptr = NULL;
-  *out_num = g_ascii_strtoull (str, &endptr, base);
-  if (errno)
-    return FALSE;
-  if (endptr == str)
-    return FALSE;
-  return TRUE;
-}
-#endif
-
 /**
  * gst_video_mastering_display_info_init:
  * @minfo: a #GstVideoMasteringDisplayInfo

meson.build

@@ -26,7 +26,7 @@ else
   have_objc = false
 endif
 
-glib_req = '>= 2.44.0'
+glib_req = '>= 2.56.0'
 orc_req = '>= 0.4.24'
 gst_req = '>= @0@.@1@.0'.format(gst_version_major, gst_version_minor)