feat(userspace/libsinsp/example): Allow running under Windows

Change command line option parsing from getopt_long to cxxopts, which
lets us run on Windows.

Initial conversion was done using Claude Sonnet 4.5, then cleaned up
manually.

cxxopts.cmake was copied from the Falco repository and updated to
version 3.1.1.

Signed-off-by: Gerald Combs <gerald@wireshark.org>

Author: geraldcombs

.github/install-deps.sh

@@ -60,3 +60,11 @@ wget -P "/usr/include" "https://raw.githubusercontent.com/troydhanson/uthash/v1.
 echo "=== Downloading BS_thread_pool.h (4.1.0) ==="
 
 wget -P "/usr/include" "https://github.com/bshoshany/thread-pool/raw/v4.1.0/include/BS_thread_pool.hpp"
+
+# === cxxopts ===
+if [ ! -f "/usr/include/cxxopts.hpp" ]; then
+    echo "=== Downloading cxxopts.hpp (3.3.1) ==="
+    wget -P "/usr/include" "https://raw.githubusercontent.com/jarro2783/cxxopts/refs/tags/v3.3.1/include/cxxopts.hpp"
+else
+    echo "=== cxxopts.hpp already exists, skipping download ==="
+fi

.github/workflows/ci.yml

@@ -204,7 +204,7 @@ jobs:
 
       - name: Install deps ⛓️
         run: |
-          HOMEBREW_NO_AUTO_UPDATE=1 brew install c-ares re2 tbb jq jsoncpp openssl uthash
+          HOMEBREW_NO_AUTO_UPDATE=1 brew install c-ares re2 tbb jq jsoncpp openssl uthash cxxopts
 
       - name: Build 🏗️
         run: |
@@ -248,7 +248,7 @@ jobs:
       - name: Install deps ⛓️
         run: |
           sudo apt update
-          sudo apt install -y --no-install-recommends ca-certificates build-essential clang-14 llvm-14 git pkg-config autoconf automake libtool libelf-dev libcap-dev linux-headers-$(uname -r)
+          sudo apt install -y --no-install-recommends ca-certificates build-essential clang-14 llvm-14 git pkg-config autoconf automake libtool libelf-dev libcap-dev libcxxopts-dev linux-headers-$(uname -r)
           sudo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-14 90
           sudo update-alternatives --install /usr/bin/llvm-strip llvm-strip /usr/bin/llvm-strip-14 90
           sudo update-alternatives --install /usr/bin/llc llc /usr/bin/llc-14 90

cmake/modules/cxxopts.cmake

@@ -0,0 +1,55 @@
+# SPDX-License-Identifier: Apache-2.0
+#
+# Copyright (C) 2026 The Falco Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+# in compliance with the License. You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software distributed under the License
+# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+# or implied. See the License for the specific language governing permissions and limitations under
+# the License.
+#
+
+#
+# cxxopts (https://github.com/jarro2783/cxxopts)
+#
+
+option(USE_BUNDLED_CXXOPTS "Enable building of the bundled cxxopts" ${USE_BUNDLED_DEPS})
+
+if(CXXOPTS_INCLUDE_DIR)
+	# we already have cxxopts
+elseif(NOT USE_BUNDLED_CXXOPTS)
+	find_package(cxxopts CONFIG)
+	if(CXXOPTS_INCLUDE_DIR)
+		get_target_property(CXXOPTS_INCLUDE_DIR cxxopts::cxxopts INTERFACE_INCLUDE_DIRECTORIES)
+	else()
+		# Was it manually installed?
+		find_path(CXXOPTS_INCLUDE_DIR cxxopts.hpp)
+		if(CXXOPTS_INCLUDE_DIR)
+			message(STATUS "Found cxxopts: include: ${CXXOPTS_INCLUDE_DIR}")
+		else()
+			message(FATAL_ERROR "Couldn't find system cxxopts")
+		endif()
+	endif()
+else()
+	set(CXXOPTS_SRC "${PROJECT_BINARY_DIR}/cxxopts-prefix/src/cxxopts/")
+	set(CXXOPTS_INCLUDE_DIR "${CXXOPTS_SRC}/include")
+
+	message(STATUS "Using bundled cxxopts in ${CXXOPTS_SRC}")
+
+	ExternalProject_Add(
+		cxxopts
+		URL "https://github.com/jarro2783/cxxopts/archive/refs/tags/v3.3.1.tar.gz"
+		URL_HASH "SHA256=3bfc70542c521d4b55a46429d808178916a579b28d048bd8c727ee76c39e2072"
+		CONFIGURE_COMMAND ""
+		BUILD_COMMAND ""
+		INSTALL_COMMAND ""
+	)
+endif()
+
+if(NOT TARGET cxxopts)
+	add_custom_target(cxxopts)
+endif()

cmake/modules/libsinsp.cmake

@@ -35,6 +35,7 @@ if(NOT HAVE_LIBSINSP)
 	include(jsoncpp)
 	include(valijson)
 	include(re2)
+	include(cxxopts)
 
 	if(ENABLE_THREAD_POOL AND NOT EMSCRIPTEN)
 		include(bs_threadpool)

userspace/libsinsp/examples/CMakeLists.txt

@@ -13,6 +13,7 @@
 # the License.
 #
 
+include(cxxopts)
 include(jsoncpp)
 
 set(sources util.cpp test.cpp)
@@ -23,6 +24,7 @@ endif()
 
 add_executable(sinsp-example ${sources})
 
+target_include_directories(sinsp-example PRIVATE "${CXXOPTS_INCLUDE_DIR}")
 target_link_libraries(sinsp-example sinsp "${JSONCPP_LIB}")
 
 if(EMSCRIPTEN)