Linux. The readline buildlink3.mk file now pulls in the correct
dependencies on its own.
+ Actually tell the configure script to use the readline dependency.
+ Add patch-ac which fixes the declaration of readline() to match the
readline.h header (it takes a const char * argument).
+ Add full DESTDIR support.
Bump the PKGREVISION to 2.
in the process. (More information on tech-pkg.)
Bump PKGREVISION and BUILDLINK_DEPENDS of all packages using libtool and
installing .la files.
Bump PKGREVISION (only) of all packages depending directly on the above
via a buildlink3 include.