configure: fix configure check for lilv-0

This should be included as `<lilv/lilv.h>`, same as is done in af_lv2.c.
Forcing the extra lilv-0 breaks platforms where the include dir is
`/usr/include/lilv/lilv.h` rather than
`/usr/include/lilv-0/lilv/lilv.h`.

The new include path works for both, because the `pkg-config --cflags`
includes `-I/usr/include/lilv-0`.

configure

@@ -5973,7 +5973,7 @@ enabled gnutls            && require_pkg_config gnutls gnutls gnutls/gnutls.h gn
 enabled jni               && { [ $target_os = "android" ] && check_header jni.h && enabled pthreads || die "ERROR: jni not found"; }
 enabled ladspa            && require_header ladspa.h
 enabled libaom            && require_pkg_config libaom "aom >= 0.1.0" aom/aom_codec.h aom_codec_version
-enabled lv2               && require_pkg_config lv2 lilv-0 "lilv-0/lilv/lilv.h" lilv_world_new
+enabled lv2               && require_pkg_config lv2 lilv-0 "lilv/lilv.h" lilv_world_new
 enabled libiec61883       && require libiec61883 libiec61883/iec61883.h iec61883_cmp_connect -lraw1394 -lavc1394 -lrom1394 -liec61883
 enabled libass            && require_pkg_config libass libass ass/ass.h ass_library_init
 enabled libbluray         && require_pkg_config libbluray libbluray libbluray/bluray.h bd_open