ports: ncurses, so zsh's line editor has a terminal to drive

zsh's configure will happily build without a terminal library -- the probe is
AC_SEARCH_LIBS, which is soft -- and produce a shell whose cursor cannot move
and whose arrow keys do nothing. ZLE is the reason to want zsh, so this comes
first.

MIT, so it combines with Apache-2.0 without conditions.

Built static, widec (which is what zsh looks for first, and the console's
UTF-8 decoder can already take), and --disable-database --with-fallbacks so
seven terminal descriptions are compiled into the library. SchOS has no
business shipping /usr/share/terminfo, and with the fallbacks the .a is
self-contained: verified that no terminfo path strings survive in the binary.

Nothing reaches sysroot/ -- a static library is not a file the OS ships -- so
`install` means into $(PREFIX). port.mk gains NCURSES beside MUSL for the
same reason MUSL is there.

tinfotest.c is the acceptance test, and asks the question the build cannot:
not "did it link" but "does terminfo work on a SchOS console". It reports
TIOCGWINSZ, initialises from the compiled-in fallback, and names every
capability ZLE binds. Anything MISSING there is a missing feature in the
shell later.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VQ7Qx8E1q1M1bbCq8QLHS2

ports/mk/port.mk

@@ -39,6 +39,11 @@ PREFIX   := $(PORTDIR)/prefix
 # fixed location so ports don't need to know where musl's own source lives.
 MUSL     := $(BUILDROOT)/musl/prefix
 
+# ncurses is the second library other ports link against, so its prefix is
+# fixed for the same reason musl's is. Unlike every other port it installs
+# nothing into sysroot/ -- a static library is not a file the OS ships.
+NCURSES  := $(BUILDROOT)/ncurses/prefix
+
 CC      := clang
 # FS register belongs to the kernel; never let the compiler touch %fs directly.
 CFLAGS_BT := -fno-stack-protector