Log Message:
Create new variables BUILDLINK_CPPFLAGS.<pkg> and BUILDLINK_LDFLAGS.<pkg>
that hold the compiler and linker flags used to find the headers and
libraries because these packages install them into non-standard places.
These variables may be used in package Makefiles by doing:

	CPPFLAGS+=	${BUILDLINK_CPPFLAGS.<pkg>}
	LDFLAGS+=	${BUILDLINK_LDFLAGS.<pkg>}