meson: build macOS signed binary as part of the default target

Signed-off-by: Emmanuel Blot <eblot@meta.com>
Tested-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
Message-ID: <20260609-macos-default-signed-bin-v1-1-e013ccb5ccb7@meta.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com>

meson.build

@@ -4453,6 +4453,7 @@ foreach target : target_dirs
       emulators += {exe['name'] : custom_target(exe['name'],
                    input: build_input,
                    output: exe['name'],
+                   build_by_default: true,
                    command: [entitlement, '@OUTPUT@', '@INPUT@'])
       }