## Use accessor functions instead direct access

GTK+ 3 removes many implementation details and struct members from its public headers. To ensure that your application does not have problems with this, you define the preprocessor symbol GSEAL_ENABLE. This will make the compiler catch all uses of direct access to struct fields so that you can go through them one by one and replace them with a call to an accessor function instead.

        make CFLAGS+="-DGSEAL_ENABLE"

Starting with 2.90.4, GTK+'s .pc files turn on GSEAL_ENABLE by default.