libedit: Update to 20260512 and fix Cygwin build

[lygstate]

• Bump snapshot to 20260512_3.1 (pkgrel 2).
• Refactor patches with _patches and apply via prepare() loop.
• Extend cygwin-build.patch with read.c sys/ioctl.h for CYGWIN.
• Remove libedit-20191231-3.1.patch; wchar_t display types break Cygwin.

[lazka]

Remove libedit-20191231-3.1.patch; wchar_t display types break Cygwin.

Could you go into detail as to why? It was added in #2241 to fix openssh

[lygstate]

The patch changes only el_display / el_vdisplay in el.h from wint_t ** to wchar_t **. That was a minimal workaround for #1697 / #2241: on Cygwin wchar_t is 16-bit (Windows ABI) while wint_t is 32-bit, and libedit treats the display buffers as wchar_t * in several places (e.g. terminal_overwrite(), casts in terminal.c). Passing a wint_t[] where wchar_t * is expected makes the prompt look truncated (sftp> -> s _).

The problem is that the patch never updated the helpers that allocate/free those buffers. terminal_alloc_buffer() and terminal_free_buffer() in terminal.c still use wint_t ** / wint_t ***, and refresh.c also mixes the two types. You noted this at merge time in #2241.

With GCC 15, -Wincompatible-pointer-types is a hard error, so the incomplete patch no longer builds. I reproduced this on 20260512 with only cygwin-build.patch + libedit-20191231-3.1.patch:

terminal.c:462:24: error: assignment to 'wchar_t **' from incompatible pointer type 'wint_t **'
terminal.c:481:30: error: passing argument 1 of 'terminal_free_buffer' from incompatible pointer type 'wchar_t ***' (expected 'wint_t ***')
refresh.c:1123:34: error: assignment to 'wint_t *' from incompatible pointer type 'wchar_t *'

The same failure happens on the current 20240808 snapshot with GCC 15.3.0, so this is not specific to the version bump; it is the toolchain catching the type mismatch that the one-line el.h hack papered over.

Without the patch, 20260512 builds cleanly with --enable-widec and cygwin-build.patch.

Open question: whether the original openssh/sftp prompt bug still reproduces without the patch on the new snapshot. I have not re-tested sftp interactively yet. If it does, we probably need either a fuller Cygwin patch (also switch terminal_alloc_buffer / terminal_free_buffer and the refresh.c sites to wchar_t, as you suggested in #2241) or an upstream fix for the wint_t/wchar_t mix on 16-bit wchar_t platforms.

[lazka]

I see, thanks for the details

[lygstate]

I see, thanks for the details

fixed the issue.