x11: add util-macros; xcb-util needs it to autoreconf

xcb-util and xcb-util-image start configure.ac with XORG_MACROS_VERSION(), so
autoreconf dies before configure runs:
  configure.ac:10: error: must install xorg-macros 1.16.0 or later before
  running autoconf/autogen
libice failed identically earlier -- it was dropped as unnecessary, but
xcb-util-image is genuinely required (plasma-desktop needs the XCB IMAGE
component), so the macros had to be ported rather than routed around.

util-macros ships only autoconf m4 text and a pkg-config file -- no compiled
code, so no cross-compilation concern. Installed into the sysroot's
share/aclocal, which is already the directory the cookbook passes to
autoreconf (-I .../sysroot//share/aclocal), so consumers need no other change.

Verified by cooking it standalone before wiring it in: builds successfully and
stages usr/share/aclocal/xorg-macros.m4. The recipe asserts that file exists,
since a silent no-op would resurface as the same "must install xorg-macros"
error in a consumer, far from the cause.

config/redbear-full.toml

@@ -290,6 +290,7 @@ libxfixes = {}
 libxi = {}
 libxrender = {}
 libxft = {}
+util-macros = {}
 xcb-util = {}
 xcb-util-image = {}
 # libice/libsm deliberately NOT included: they are X11 session-management

recipes/x11/util-macros/recipe.toml

@@ -0,0 +1,46 @@
+[package]
+name = "util-macros"
+version = "1.20.2"
+description = "X.Org autoconf macros (xorg-macros.m4)"
+
+# util-macros ships ONLY autoconf m4 macros -- no compiled code, no target
+# libraries. It is a BUILD-TIME dependency of most X.Org autotools packages,
+# whose configure.ac starts with XORG_MACROS_VERSION(...). Without it autoreconf
+# fails before configure even runs:
+#   configure.ac:10: error: must install xorg-macros 1.16.0 or later before
+#   running autoconf/autogen
+# (first hit: xcb-util, which plasma-desktop needs for the XCB IMAGE component;
+# libice fails the same way.)
+#
+# The macros are installed into the SYSROOT's share/aclocal because that is the
+# directory the cookbook already passes to autoreconf:
+#   autoreconf -fvi -I .../sysroot//share/aclocal
+# so nothing else has to change for consumers to find them.
+#
+# Architecture-independent by construction: the tarball contains .m4 text and a
+# pkg-config file, so there is no cross-compilation concern.
+
+[source]
+tar = "https://www.x.org/releases/individual/util/util-macros-1.20.2.tar.xz"
+blake3 = "ad272a006b269e3925bc700dd1e51c1b8d8fa3a825dfc0aecfeeef3db38a94f0"
+
+[build]
+template = "custom"
+dependencies = []
+script = """
+DYNAMIC_INIT
+
+# No compilation: configure + install just copies xorg-macros.m4 and the
+# xorg-macros.pc describing it. --prefix=/usr with DESTDIR so the absolute
+# datadir lands inside the stage rather than on the build host.
+"${COOKBOOK_SOURCE}/configure" --prefix=/usr
+make install DESTDIR="${COOKBOOK_STAGE}"
+
+# Assert the macro file actually landed. A silent no-op here would resurface as
+# the same "must install xorg-macros" failure in a consumer, far from this
+# recipe -- exactly the far-from-the-cause pattern the empty-package gate exists
+# to catch.
+test -f "${COOKBOOK_STAGE}/usr/share/aclocal/xorg-macros.m4" \
+    || { echo "ERROR: xorg-macros.m4 not staged" >&2; \
+         find "${COOKBOOK_STAGE}" -name '*.m4' >&2; exit 1; }
+"""

recipes/x11/xcb-util-image/recipe.toml

@@ -11,6 +11,8 @@ autotools_recursive_regenerate
 
 [build]
 dependencies = [
+    # XORG_MACROS_VERSION() in configure.ac -- autoreconf fails without it.
+    "util-macros",
     "xcb-util",
 ]
 template = "custom"

recipes/x11/xcb-util/recipe.toml

@@ -11,6 +11,8 @@ autotools_recursive_regenerate
 
 [build]
 dependencies = [
+    # XORG_MACROS_VERSION() in configure.ac -- autoreconf fails without it.
+    "util-macros",
     "libxcb",
 ]
 template = "custom"