WebAssembly: Disable subdirectory configuration for unsupported LD

WebAssembly: Disable subdirectory configuration for unsupported LD

Remove an LD subdirectory configuration error:

*** ld does not support target wasm32-unknown-none
*** see ld/configure.tgt for supported targets
make[1]: *** [configure-ld] Error 1

which prevents binutils for the WebAssembly target from being built
unless an explicit `--disable-ld' configuration option has been given.
Users must not have to disable features selected by default to get a
working configuration.

	/
	* configure.ac <wasm32-*-*> (noconfigdirs): Add `ld'.
	* configure: Regenerate.