Revert "meson: Define G_OS_DARWIN when compiling under OSX or iOS"

This reverts commit e85635daa0.

See the previous revert for rationale.

Fixes: #2802

docs/reference/glib/glib-overrides.txt

@@ -196,11 +196,6 @@ GCond *cond
 
 # Definitions for different operating systems
 
-<MACRO>
-<NAME>G_OS_DARWIN</NAME>
-#define G_OS_DARWIN
-</MACRO>
-
 <MACRO>
 <NAME>G_OS_UNIX</NAME>
 #define G_OS_UNIX

docs/reference/glib/glib-sections.txt.in

@@ -140,7 +140,6 @@ GLIB_VERSION_PREV_STABLE
 <TITLE>Standard Macros</TITLE>
 <FILE>macros</FILE>
 <SUBSECTION>
-G_OS_DARWIN
 G_OS_WIN32
 G_OS_UNIX
 

glib/docs.c

@@ -1997,17 +1997,6 @@
  * These macros provide a few commonly-used features.
  */
 
-/**
- * G_OS_DARWIN:
- *
- * This macro is defined only on Apple operating systems (macOS or iOS).
- * So you can bracket Apple-specific code in `\#ifdef G_OS_DARWIN`.
- *
- * Note that %G_OS_UNIX is also set.
- *
- * Since: 2.76
- */
-
 /**
  * G_OS_WIN32:
  *

glib/tests/macros.c

@@ -20,19 +20,8 @@
  * Author: Philip Withnall <withnall@endlessm.com>
  */
 
-#include "config.h"
-
 #include <glib.h>
 
-#if defined (__APPLE__) || defined (HAVE_COCOA) || defined (HAVE_CARBON)
-# ifndef G_OS_UNIX
-  G_STATIC_ASSERT (FALSE);
-# endif
-# ifndef G_OS_DARWIN
-  G_STATIC_ASSERT (FALSE);
-# endif
-#endif
-
 /* Test that G_STATIC_ASSERT_EXPR can be used as an expression */
 static void
 test_assert_static (void)

meson.build

@@ -276,9 +276,6 @@ if host_system == 'windows'
 elif host_system == 'cygwin'
   glib_os = '''#define G_OS_UNIX
 #define G_WITH_CYGWIN'''
-elif host_system in ['darwin', 'ios']
-  glib_os = '''#define G_OS_UNIX
-#define G_OS_DARWIN'''
 else
   glib_os = '#define G_OS_UNIX'
 endif