disable legacy GTK UI from default cmake option

CMakeLists.txt

@@ -43,7 +43,7 @@ option(ENABLE_DATE "Use build date in internal version number." NO)
 option(ENABLE_DAEMON "Enable the linphone daemon interface." YES)
 option(ENABLE_DOC "Enable documentation generation with Doxygen." YES)
 option(ENABLE_JAVADOC "Add a target to generate documentation for Java API" NO)
-option(ENABLE_GTK_UI "Turn on or off compilation of gtk interface." YES)
+option(ENABLE_GTK_UI "Turn on or off compilation of gtk interface." NO)
 option(ENABLE_LDAP "Enable LDAP support." NO)
 option(ENABLE_SQLITE_STORAGE "Turn on compilation sqlite storage, for messages, contacts, history" YES)
 cmake_dependent_option(ENABLE_LIME "Enable Instant Messaging Encryption." YES "ENABLE_SQLITE_STORAGE" NO)