[ADD] nlohmann-json, and three more packages without their docs

nlohmann-json is a real closure gap, not a documentation cut: both cmake and
cppdap stop on "Could NOT find nlohmann_json". It is a header-only C++ library,
one of the cheapest packages in the list, and cmake is not optional -- the
cmake/cppdap/jsoncpp/libuv group behind it is what several other packages build
with.

The other three are doxygen and sphinx again. jsoncpp's is the least readable
failure in the port so far: doxybuild.py is handed an empty doxygen path and
raises Exception('path is empty.'), so a missing tool arrives as a Python
traceback about a path.

libuv needed two places -- `make man -C docs` and the install of
docs/build/man/libuv.1 -- the same shape as libxml2's docs split and pam's PDFs:
a failure on a path at the end of package(), after a compile that worked.

--- FR ---

nlohmann-json est un vrai trou de fermeture, pas une coupe de documentation :
cmake et cppdap s'arrêtent tous deux sur « Could NOT find nlohmann_json ». C'est
une bibliothèque C++ d'en-têtes seuls, l'un des paquets les moins chers de la
liste, et cmake n'est pas optionnel — le groupe cmake/cppdap/jsoncpp/libuv
derrière lui est ce avec quoi plusieurs autres se bâtissent.

Les trois autres sont encore doxygen et sphinx. Celui de jsoncpp est l'échec le
moins lisible du portage jusqu'ici : doxybuild.py reçoit un chemin de doxygen
vide et lève Exception('path is empty.'), donc un outil manquant arrive sous la
forme d'une trace Python parlant d'un chemin.

libuv demandait deux endroits — `make man -C docs` et l'installation de
docs/build/man/libuv.1 — même forme que le découpage de libxml2 et les PDF de
pam : un échec sur un chemin en fin de package(), après une compilation réussie.

Assisted-by: Claude Opus 5

patches/pkgbuild/jsoncpp.sh

@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+# jsoncpp: no doxygen build.
+#
+#   File "doxybuild.py", line 82, in assert_is_exe
+#     raise Exception('path is empty.')
+#
+# A python traceback, which is what makes this one hard to read: doxybuild.py was
+# handed an empty doxygen path because there is no doxygen, and it reports that
+# as a path problem. build() runs it after the compile has already finished.
+set -euo pipefail
+python3 - <<'ZZPY'
+import io, re
+lines = io.open("PKGBUILD", encoding="utf-8").read().split("\n")
+# The call spans several lines: find it and drop through its last continuation.
+hit = [i for i, l in enumerate(lines) if re.search(r"python doxybuild\.py", l)]
+assert len(hit) == 1, "jsoncpp: expected one doxybuild call, got %d" % len(hit)
+i = hit[0]
+j = i
+while lines[j].rstrip().endswith("\\"):
+    j += 1
+del lines[i:j + 1]
+# The `echo "Building docs..."` above it would now announce nothing.
+if i > 0 and "Building docs" in lines[i - 1]:
+    del lines[i - 1]
+io.open("PKGBUILD", "w", encoding="utf-8").write("\n".join(lines))
+ZZPY
+grep -q "doxybuild" PKGBUILD && { echo "jsoncpp: doxybuild survived" >&2; exit 1; }
+echo "jsoncpp: doxygen build removed"

patches/pkgbuild/libevent.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+# libevent: no Doxygen API reference.
+#
+#   -- Could NOT find Doxygen (missing: DOXYGEN_EXECUTABLE)
+#   CMake Error at cmake/UseDoxygen.cmake:108 (message):
+#
+# EVENT__DOXYGEN=ON makes it a hard requirement. doxygen is the most expensive of
+# the documentation tools this port declined -- it wants clang, fmt, spdlog and
+# llvm-libs, an entire compiler infrastructure to produce HTML.
+set -euo pipefail
+python3 - <<'ZZPY'
+import io
+s = io.open("PKGBUILD", encoding="utf-8").read()
+old = "-D EVENT__DOXYGEN=ON"
+assert s.count(old) == 1, "libevent: expected one EVENT__DOXYGEN, got %d" % s.count(old)
+s = s.replace(old, "-D EVENT__DOXYGEN=OFF", 1)
+io.open("PKGBUILD", "w", encoding="utf-8").write(s)
+ZZPY
+grep -q "EVENT__DOXYGEN=OFF" PKGBUILD || { echo "libevent: doxygen not disabled" >&2; exit 1; }
+echo "libevent: Doxygen reference disabled"

patches/pkgbuild/libuv.sh

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+# libuv: no man page.
+#
+#   Makefile:14: *** The 'sphinx-build' command was not found.
+#
+# TWO PLACES: `make man -C docs` builds it and package() installs
+# docs/build/man/libuv.1. Removing only the build gives
+#
+#   install: cannot stat 'docs/build/man/libuv.1'
+#
+# which is the same shape as libxml2's docs split and pam's PDFs -- a failure on
+# a path, at the end of package(), after a compile that worked.
+set -euo pipefail
+python3 - <<'ZZPY'
+import io, re
+lines = io.open("PKGBUILD", encoding="utf-8").read().split("\n")
+mk = [i for i, l in enumerate(lines) if re.search(r"make man -C docs", l)]
+assert len(mk) == 1, "libuv: expected one `make man -C docs`, got %d" % len(mk)
+inst = [i for i, l in enumerate(lines) if "docs/build/man/libuv.1" in l]
+assert len(inst) == 1, "libuv: expected one man install, got %d" % len(inst)
+i = inst[0]
+# The install spans two lines: the source and the destination.
+j = i
+while lines[j].rstrip().endswith("\\"):
+    j += 1
+del lines[i:j + 1]
+del lines[mk[0]]
+io.open("PKGBUILD", "w", encoding="utf-8").write("\n".join(lines))
+ZZPY
+grep -qE "make man -C docs|libuv\.1" PKGBUILD && {
+    echo "libuv: a man page reference survived" >&2; exit 1; }
+echo "libuv: man page dropped (no sphinx)"

scripts/packages.sh

@@ -261,6 +261,15 @@ STAGE1_PACKAGES=(
     # runtimes behind doxygen or asciidoctor, so it is cheaper to build than to
     # hook around.
     scdoc
+    # nlohmann-json: a real closure gap, not a documentation cut. BOTH cmake and
+    # cppdap stop on
+    #
+    #   Could NOT find nlohmann_json (missing: nlohmann_json_DIR)
+    #
+    # It is a header-only C++ library -- one of the cheapest packages in this
+    # list -- and cmake is not optional here: the whole cmake/cppdap/jsoncpp/
+    # libuv group behind it is what several other packages build with.
+    nlohmann-json
     # libxslt stays in the list because it is part of the distribution, but
     # STAGE 1 CANNOT BUILD IT:
     #