specified in the top level Makefiles.
Previously I missed dozens of Makefiles that skip the install after
using `cmp -s' to decide that the install isn't necessary.
as tn3270 can replace _putchar(0 with their own routine and still keep
using the __cputchar() routine used by all of the other curses routines.
Reviewed by: "Andrey A. Chernov, Black Mage" <ache@astral.msk.su>
