Ensure that the <readline/history.h> link to <readline/readline.h> is
installed too for 'make includes'. Also, avoid creating obj dir.
This is finally real fix for lib/12929.
XXX Is this right?
them there.
readline.h of libedit had to move to subdirectory 'readline', due to the way
BSD makefiles work; this is better than potentially fragile Makefile hacks