[glib/wip/3v1n0/add-darwin-os] meson: Define G_OS_DARWIN when compiling under OSX or iOS

[Marco Trevisan <marcotrevi src gnome org>]

commit 53fc954d86c1d733f6738ce308c7c43a107cc476
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Tue Oct 18 21:59:59 2022 +0200

    meson: Define G_OS_DARWIN when compiling under OSX or iOS
    
    It has enough differences to expose it as an unix-subtype.

 docs/reference/glib/glib-sections.txt.in |  1 +
 glib/docs.c                              | 11 +++++++++++
 meson.build                              |  3 +++
 3 files changed, 15 insertions(+)
---
diff --git a/docs/reference/glib/glib-sections.txt.in b/docs/reference/glib/glib-sections.txt.in
index 35a20efcbc..90b0f32585 100644
--- a/docs/reference/glib/glib-sections.txt.in
+++ b/docs/reference/glib/glib-sections.txt.in
@@ -140,6 +140,7 @@ GLIB_VERSION_PREV_STABLE
 <TITLE>Standard Macros</TITLE>
 <FILE>macros</FILE>
 <SUBSECTION>
+G_OS_DARWIN
 G_OS_WIN32
 G_OS_UNIX
 
diff --git a/glib/docs.c b/glib/docs.c
index a8e31fb873..968d2e20f5 100644
--- a/glib/docs.c
+++ b/glib/docs.c
@@ -1647,6 +1647,17 @@
  * These macros provide a few commonly-used features.
  */
 
+/**
+ * G_OS_DARWIN:
+ *
+ * This macro is defined only on Mac OS (OSX or iOS). So you can bracket
+ * -specific code in "\#ifdef G_OS_DARWIN".
+ *
+ * Note that %G_OS_UNIX is also set.
+ *
+ * Since: 2.76
+ */
+
 /**
  * G_OS_WIN32:
  *
diff --git a/meson.build b/meson.build
index ddcdc028d4..bd30f53d7a 100644
--- a/meson.build
+++ b/meson.build
@@ -235,6 +235,9 @@ if host_system == 'windows'
 elif host_system == 'cygwin'
   glib_os = '''#define G_OS_UNIX
 #define G_WITH_CYGWIN'''
+elif host_system == 'darwin'
+  glib_os = '''#define G_OS_UNIX
+#define G_OS_DARWIN'''
 else
   glib_os = '#define G_OS_UNIX'
 endif