mutt on macOS and --with-curses=DIR

Hi there,

I use mutt on macOS. For software that I install only for me, I use
--prefix=$HOME/sw.

macOS comes with a relatively old version of ncurses. The header files
in the system-wide include directory look like this:

include/curses.h
include/ncurses.h -> curses.h

To be able to use a more recent version of ncurses, I installed one in
$HOME/sw. The header files are located in a directory named ncursesw
under $HOME/sw/include (ncursesw default) and look like this:

include/ncursesw/curses.h
include/ncursesw/ncurses.h -> curses.h

Among others, I use the following configure options:

--prefix=$HOME/sw --with-curses=$HOME/sw

Unfortunately, configure doesn't seem to be able to find ncurses in
$HOME/sw. It finds the system-wide ncurses library instead, and later
mutt is linked against that one.

% grep CURSES config.h
/* #undef HAVE_NCURSESW_NCURSES_H */
#define HAVE_NCURSES_H 1
/* #undef HAVE_NCURSES_NCURSES_H */
/* #undef USE_SLANG_CURSES */

(otool on macOS is like ldd)

% otool -L $HOME/sw/bin/mutt | grep curses
	/usr/lib/libncurses.5.4.dylib (compatibility version 5.4.0, current version 5.4.0)

This works with other apps like tin, lynx, or vifm; ncurses is found in
$HOME/sw, and the executables are linked against it.

% otool -L $HOME/sw/bin/vifm | grep curses
	/Users/dennis/sw/lib/libncursesw.6.dylib (compatibility version 6.0.0, current version 6.0.0)

It looks like --with-ncurses=DIR is being ignored for some reason, or at
least isn't having the desired effect.

If it helps, I can send the config.log; it's about 1 MiB in size.

Dennis