authn: correct meson behaviors

Today `basic-auth` (and other options) can be enabled even if
`insecure-disable-auth` is enabled, which doesn't make sense.
With this block this commit added in meson, If we disable authx with
`insecure-disable-auth`, then all these auth options will be ignored.

Tested:
1. code compiles with and without 'insecure-disable-auth'.
2. No new service validator errors when 'insecure-disable-auth' is
turned on.
3. No new service validator errors when 'insecure-disable-auth' is
turned off.

Signed-off-by: Nan Zhou <nanzhoumails@gmail.com>
Change-Id: I2c634851f7aa7b9e57158770c5d40c12954c93a7
diff --git a/meson.build b/meson.build
index 7be259b..ec70510 100644
--- a/meson.build
+++ b/meson.build
@@ -101,6 +101,11 @@
         add_project_arguments(option_value,language:'cpp')
         summary(option_key,option_value, section : 'Enabled Features')
       endif
+    elif (option_key in ['basic-auth', 'cookie-auth', 'session-auth', 'xtoken-auth', 'mutual-tls-auth'])
+      if (get_option('insecure-disable-auth').disabled())
+        add_project_arguments(option_value, language:'cpp')
+        summary(option_key,option_value, section : 'Enabled Features')
+      endif
     else
       summary(option_key,option_value, section : 'Enabled Features')
       add_project_arguments(option_value,language:'cpp')