meson: Use osdep_prefix for strchrnul()

macOS SDK may have the symbol of strchrnul(), but it is actually
available only on macOS 15.4 or later and that fact is codified in
string.h. Include the header file using osdep_prefix to check if the
function is available on the deployment target.

Cc: [email protected]
Signed-off-by: Akihiko Odaki <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Tested-by: Philippe Mathieu-Daudé <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Philippe Mathieu-Daudé <[email protected]>
(cherry picked from commit a5b30be)
Signed-off-by: Michael Tokarev <[email protected]>

Author: akihikodaki

meson.build

@@ -2193,6 +2193,7 @@ osdep_prefix = '''
   #include <stddef.h>
   #include <sys/types.h>
 
+  #include <string.h>
   #include <limits.h>
   /* Put unistd.h before time.h as that triggers localtime_r/gmtime_r
    * function availability on recentish Mingw-w64 platforms. */
@@ -2657,7 +2658,7 @@ config_host_data.set('HAVE_GETIFADDRS', cc.has_function('getifaddrs'))
 config_host_data.set('HAVE_GLIB_WITH_SLICE_ALLOCATOR', glib_has_gslice)
 config_host_data.set('HAVE_GLIB_WITH_ALIGNED_ALLOC', glib_has_aligned_alloc)
 config_host_data.set('HAVE_OPENPTY', cc.has_function('openpty', dependencies: util))
-config_host_data.set('HAVE_STRCHRNUL', cc.has_function('strchrnul'))
+config_host_data.set('HAVE_STRCHRNUL', cc.has_function('strchrnul', prefix: osdep_prefix))
 config_host_data.set('HAVE_SYSTEM_FUNCTION', cc.has_function('system', prefix: '#include <stdlib.h>'))
 if rbd.found()
   config_host_data.set('HAVE_RBD_NAMESPACE_EXISTS',