ncurses: add the terminal dependency root

[brandonpayton]

Purpose

Add ncurses as Kandelo's terminal-library dependency root. The formula builds the wide-character static C and C++ interfaces, debug variants, conventional compatibility names, pkg-config metadata, guest utilities, manpages, compiled fallbacks, and the full terminfo database.

This unblocks dependency-first migrations for shells, editors, terminal tools, and other CLI packages.

Platform prerequisites

Bottle publication remains gated on the open Kandelo platform chain:

• #842 supplies the shared SDK main-thread stack needed by ncurses' nested terminfo reader frames.
• #867 fixes pthread fork continuation corruption and establishes ABI 18.
• #873 builds fork instrumentation from the repository workspace.
• #882 rejects stale artifacts with aliased ABI exports.
• #885 publishes tap-native formulas without registry duplicates.

The formula deliberately does not inject a package-specific stack flag. Static ncurses cannot own a final executable's stack, and doing so would hide the same platform defect from other software.

Formula contract

• Builds wasm32 normal and debug static libraries for ncurses, terminfo, form, menu, panel, and the C++ binding.
• Uses the tap's libcxx formula for the C++ binding.
• Installs wide, conventional, termcap, top-level-header, and namespaced-header compatibility interfaces.
• Builds host tic/infocmp only for architecture-independent data generation.
• Ships more than 2,000 compiled terminal entries plus isolated compiled-in fallbacks.
• Binds compiled terminfo lookup and config scripts to /home/linuxbrew/.linuxbrew/opt/ncurses, never the build host's keg.
• Runs target tic, tput, and infocmp under Kandelo and verifies a generated custom terminal entry.
• Exercises C, C++, pkg-config, termcap, header compatibility, fallback lookup, and non-fallback disk lookup paths.

Generator portability fix

Upstream MKfallback.sh uses GNU sed's \<...\> word-boundary syntax to rewrite generated short arrays to NCURSES_INT2. Darwin sed silently leaves that expression unchanged. With target extended colors enabled, the resulting fallback table stored 16-bit numbers while ncurses read the TERMTYPE2 table as 32-bit numbers, so setupterm() succeeded but numeric capabilities such as colors were misindexed.

The formula rewrites that generator expression to a portable, declaration-specific substitution and rejects a generated fallback table with the wrong target width.

Validation

Local evidence using scripts/dev-shell.sh and the ABI 18 integration worktree:

• Exact current formula source build and install: passed.
• brew test automattic/kandelo-homebrew/ncurses: passed, including isolated compiled fallback, disk database, target tic output, C, C++, pkg-config, termcap, and header compatibility paths.
• Corrected fallback.o: xterm_256color_number_data occupies the expected 32-bit layout before xterm_256color_string_data (0x130 to 0x1d0).
• Installed libraries contain /home/linuxbrew/.linuxbrew/opt/ncurses/share/terminfo and no /Users/brandon/emdash build path.
• Local wasm32_kandelo bottle generation and normal resolver pour: passed; SHA-256 a61108273dfaee86c4b036d30ce26455c33f738efa3dfaf019d8d53e9803a33b.
• The full formula test passed again from the poured bottle.
• brew style: no offenses.
• Ruby syntax and git diff --check: passed.

brew audit is not claimed: the cross-target's intentional top-level compatibility headers trigger Homebrew's macOS system-header shadow rule. Publication and merge remain gated on the platform PRs above.

[brandonpayton]

Rebased onto current tap main through #13 to remove the README-only conflict.

• the Formula/ncurses.rb blob is byte-for-byte unchanged (d3fc1905c1a679058311b08673636fbde72181bc before and after)
• the README resolution preserves the ncurses, sed, gzip, and grep entries
• Homebrew portable Ruby reports Syntax OK
• git diff --check origin/main...HEAD passes
• GitHub now reports the PR mergeable

No ABI 18 artifact rebuild or runtime claim was added by this rebase. The existing #842/#867 and bottle-publication gates remain in force.