Use #pragma once in all of our header files
There seems to be no reason to stick to the old header guards.
I didn't change the header files from qxmpp-exts or hsluv-c since those projects don't use #pragma once.
There seems to be no reason to stick to the old header guards.
I didn't change the header files from qxmpp-exts or hsluv-c since those projects don't use #pragma once.