This trips up when using libebook:

In file included from /usr/include/evolution-data-server/camel/camel-session.h:32,
                 from /usr/include/evolution-data-server/camel/camel-cipher-context.h:28,
                 from /usr/include/evolution-data-server/camel/camel.h:30,
                 from /usr/include/evolution-data-server/libedataserver/e-source-camel.h:25,
                 from /usr/include/evolution-data-server/libedataserver/libedataserver.h:61,
                 from /usr/include/evolution-data-server/libebook-contacts/libebook-contacts.h:23,
                 from ../src/chatty-conversation.c:20:
/usr/include/evolution-data-server/camel/camel-provider.h:102:33: error: result of ‘1 << 31’ requires 33 bits to represent, but ‘int’ only has 32 bits [-Werror=shift-overflow=]
  CAMEL_URL_PATH_IS_ABSOLUTE = 1 << 31,