Support Motif on the compat stack

[jserv]

This adds lib{Xmu,Xpm,Xext}-compat shared libraries for the active Motif fork[1] alongside the existing libXt-compat, and rework the Xrm resource cascade, event layer, and font surface so its widgets function.

Xrm: matchEntry returns a per-component specificity vector compared with memcmp, replacing the flat-sum scoring that violated Xt precedence; XrmEnumerateDatabase honors loose-bound entries so *background-style resources surface under any prefix; parseLine and entryPatternToString decode and re-encode \n, \t, \r, \, and octal escapes so XtParseTranslationTable consumers see the byte values their grammars expect.

Events and input: convertModifierState maps KMOD_ALT to Mod1Mask and KMOD_NUM to Mod2Mask; XK_Alt_R joins XK_Alt_L on Mod1Mask in XkbKeysymToModifiers and the XGetModifierMapping table. XSetInputFocus drives keyboardFocus instead of warning; XGrabKey / XUngrabKey track passive grabs; XGrabKeyboard / XUngrabKeyboard track a modal grab; the event layer routes key events through grabs before falling back to focus. The implicit setKeyboardFocus calls in XSelectInput and XMapWindow are removed so XSetInputFocus is the sole focus authority. postEvent ClientMessage uses calloc, sets send_event = True, and carries a timestamp in data.l[1] for ICCCM compliance. getEventQueueLength lifts its peek buffer from 25 to 256 so expose and configure bursts during Motif geometry negotiation are not silently truncated.

Bounds and threading: parsePositiveInt guards INT_MAX before each XLFD digit multiply; decodeString bounds-checks every \x, \u, and trailing-backslash payload; the text-render cache wraps lookup, insert, eviction, and the dependent SDL_RenderCopy under one SDL_mutex so concurrent evictions cannot free a texture mid-draw.

XSetRGBColormaps and XGetRGBColormaps replace WARN_UNIMPLEMENTED stubs with the ICCCM 6.4 ten-CARD32 wire format (visualid, killid, colormap, red_max, red_mult, green_max, green_mult, blue_max, blue_mult, base_pixel). XmuLookupStandardColormap uses them to synthesize a 24bpp RGB cube on the root window when the requested visual is not already installed. destroyWindow loses its vestigial WARN_UNIMPLEMENTED that was firing on every Motif demo teardown.

Build glue: mk/libxpm.mk pins libXpm-3.5.19; mk/xcompat-libs.mk links the new compat libraries against libXt-compat and libX11-compat; mk/pkgconfig.mk emits x11/xt/xpm/xmu/xext .pc files so motif's autotools configure resolves the compat stack instead of host X11; mk/motif.mk clones the pinned motif fork, runs autoreconf and configure quietly (V=1 to surface details, per-stage log files redirected on failure), and stages lib{Xm,Mrm}.so plus the upstream demos. A new shared_lib_rpath_ldflags macro in mk/common.mk consolidates the Linux $ORIGIN / Darwin @rpath+@loader_path conditionals; mk/deps.mk aggregates per-fragment dep files via $(ALL_DEPS).

Tests: XSet/GetRGBColormaps round-trip exercising all ten wire fields, XkbKeysymToModifiers including XK_Alt_R on Mod1Mask, libXt resource cascade enumeration with mixed tight and loose bindings, Xmu converter address pinning so a dropped converter fails at link, plus lib{xpm,xt,xmu} and motif link-and-resource binaries. make check reports 31 ok markers in release and debug (CFLAGS_EXTRA=-DDEBUG_LIBX11_COMPAT) builds.

[1] https://github.com/thentenaar/motif

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Summary by cubic

Adds Motif support to the compat stack with new Xmu/Xpm/Xext/Xinerama shims, pkg-config metadata, and a make motif build target. Implements full Shape masks with per‑pixel compositing and upgrades Xrm/XIM/events so Motif widgets link and render correctly.

• New Features

  • Compat libs and tooling: libXmu-compat, libXpm-compat, libXext-compat, libXinerama-compat; pkg-config for x11, xt, xpm, xmu, xext, xinerama; make motif builds the pinned fork and stages libXm, libMrm, demos, and helper scripts (validate, profile, diff, screenshots).
  • Shape: bounding/clip masks with XShape* combine/query and per‑pixel compositing across all draw paths (copy, fills, lines, text, clears, XPutImage); tests cover single/intersection/combine semantics.
  • Events/input: Mod1/Mod2 mapping, passive XGrabKey and modal XGrabKeyboard, XSetInputFocus as sole focus authority, OSF keysyms, larger queue, deferred/coalesced presents and child expose propagation; per‑Display last request code with mutex‑guarded tracking for accurate XErrorEvent.
  • Xrm/XIM/Fonts: per‑component specificity and loose‑binding; escape parsing (\n, \t, \r, \\, octal); UTF‑8/XIM/XOM (Xutf8*, XSetOCValues/XGetOCValues, XOMOfOC) and text‑extent APIs; GC font ref‑counting and cache invalidation; bounds checks in XLFD/string decoders.
  • ICCCM/Colormaps and utils: XSet/GetRGBColormaps; XmuLookupStandardColormap synthesizes a 24bpp RGB cube; XReadBitmapFileData; link tests for xmu, xpm, xinerama; Motif link/resource and visible rendering tests; Motif examples (hello, simpleapp, togglebox).
  • Build/runtime: rpath on Linux ($ORIGIN) and macOS (install_name @rpath/<self> + @loader_path); SDL wrapper libs libSDL2-x11compat and libSDL2_ttf-x11compat with sanitizer‑safe loading (auto‑disable RTLD_DEEPBIND) and atomic dlsym caching; upstream headers synced to libX11 1.8.13; stub X11/SM/SM.h.
  • CI: GitHub Actions runs lint/build/debug/sanitize/motif in parallel with content‑addressed caches (upstream headers, Motif clone, per‑job ccache); the Motif job builds all demos and validates under SDL_VIDEODRIVER=dummy (Linux sets MOTIF_YACC="bison -y").

• Migration

  • Set PKG_CONFIG_PATH=$PWD/build/pkgconfig so autotools resolve x11, xt, xpm, xmu, xext, xinerama to the compat libs.
  • Run make motif to build Motif against the compat stack; demos are staged and can be validated/profiled with the provided scripts.
  • No LD_LIBRARY_PATH needed when linking via the provided .pc files; rpath is set for Linux/macOS as above.

^{Written for commit 4886eae. Summary will update on new commits.}

[jserv]

Steps to build Motif demo programs:

make motif-demos

Run one of demo programs:

build/motif-demos/demos/programs/piano/piano