[gtk-vnc] meson: drop x11 min version back further for Ubuntu 16.04

[Daniel P. Berrange <dberrange src gnome org>]

commit bf6a5651f74c829c56a7e58eefeea6abf5dc9de5
Author: Daniel P. Berrangé <dan berrange com>
Date:   Wed Jan 8 17:39:22 2020 +0000

    meson: drop x11 min version back further for Ubuntu 16.04
    
    Signed-off-by: Daniel P. Berrangé <berrange redhat com>

 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index 525c41a..66d7ee3 100644
--- a/meson.build
+++ b/meson.build
@@ -65,7 +65,7 @@ libsasl_min_version = '2.1.26'
 # gtk-vnc
 gtk_min_version = '3.0.0'
 cairo_min_version = '1.2.0'
-x11_min_version = '1.6.4'
+x11_min_version = '1.6.0'
 
 # gvncpule
 libpulse_min_version = '10.0'