some header bugs

[DJ Delorie]

> The distributed version of libtermcap.a is an actual library.  I don't
> release a DLL.

OK, this time I'm going to think first.

This is what happens:

configure sees that -lncurses works, but can't find
<ncurses/termcap.h> to uses <termcap.h> instead, since it does find
that.  Ncurses defaults linking against a dll.

The latest texinfo sources have a new check specifically for these
variables, which results in info being linked against both ncurses and
termcap, one for the functions and one for the variables.  This can't
be a good thing.

However, this older texinfo (which is what I'm working on, don't ask)
doesn't have that test.  Try building
latest/texinfo/texinfo-src.tar.gz with the current cygwin stuff.

Suggestions for the right way to fix this?