This add a new pgp_armor_headers function to extract armor headers from an
ASCII-armored blob, and a new overloaded variant of the armor function, for
constructing an ASCII-armor with extra headers.
Marko Tiikkaja and me.
Instead of trying to accurately calculate the space needed, use a StringInfo
that's enlarged as needed. This is just moving things around currently - the
old code was not wrong - but this is in preparation for a patch that adds
support for extra armor headers, and would make the space calculation more
complicated.
Marko Tiikkaja
pgp.h used to require including mbuf.h and px.h first. Include those in
pgp.h, so that it can be used without prerequisites. Remove mbuf.h
inclusions in .c files where mbuf.h features are not used
directly. (px.h was always used.)
