doc: Make sure we parse the server and sftp documentation

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>

doc/CMakeLists.txt

@@ -15,6 +15,8 @@ if (DOXYGEN_FOUND)
     set(DOXYGEN_MARKDOWN_SUPPORT YES)
 
     set(DOXYGEN_PREDEFINED DOXYGEN
+                           WITH_SERVER
+                           WITH_SFTP
                            PRINTF_ATTRIBUTE(x,y))
 
     set(DOXYGEN_EXCLUDE ${CMAKE_CURRENT_SOURCE_DIR}/that_style)