configure, meson: convert libusb detection to meson

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/meson_options.txt b/meson_options.txt
index ac6e90d..02c14d4 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -86,6 +86,8 @@
        description: 'libgcrypt cryptography support')
 option('libudev', type : 'feature', value : 'auto',
        description: 'Use libudev to enumerate host devices')
+option('libusb', type : 'feature', value : 'auto',
+       description: 'libusb support for USB passthrough')
 option('lzfse', type : 'feature', value : 'auto',
        description: 'lzfse support for DMG images')
 option('lzo', type : 'feature', value : 'auto',