configure: Improve TCI feature description

Users might want to enable all features, without realizing some
features have negative effect. Mention the TCI feature is slow
and experimental, hoping it will be selected knowingly.

Suggested-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20210125144530.2837481-3-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/meson_options.txt b/meson_options.txt
index 95f1079..675a9c5 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -40,7 +40,7 @@
 option('tcg', type: 'feature', value: 'auto',
        description: 'TCG support')
 option('tcg_interpreter', type: 'boolean', value: false,
-       description: 'TCG bytecode interpreter (TCI)')
+       description: 'TCG with bytecode interpreter (experimental and slow)')
 option('cfi', type: 'boolean', value: 'false',
        description: 'Control-Flow Integrity (CFI)')
 option('cfi_debug', type: 'boolean', value: 'false',