camera_streamer: add cross_build.sh and deploy_sender.py development tools

examples/camera_streamer/argus_sender/TESTING.md

@@ -34,6 +34,13 @@ The deployment snapshot/restore checks run from `argus_sender/`:
 python3 -m pytest tests/test_deployment.py -q
 ```
 
+## Cross-compiling on a PC
+
+`cross_build.sh syntax` type-checks every sender source against the Orin's headers, and `cross_build.sh build`
+produces an aarch64 `argus_sender` that is linked but not run. Both use the sysroot and Arm toolchain from
+`ORIN_CROSS_ROOT`; the script header says what the sysroot must contain. Tests that include Argus headers compile
+this way but run only on the Orin.
+
 ## 120-frame hardware smoke test
 
 The opt-in test opens the devices in

examples/camera_streamer/argus_sender/cross_build.sh

@@ -0,0 +1,68 @@
+#!/usr/bin/env bash
+# SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+# Cross-compile argus_sender for a Jetson on an x86 PC, using an Orin sysroot and an Arm GNU toolchain under
+# ORIN_CROSS_ROOT (default ~/github/orin-cross-39.2.1):
+#   <root>/sysroot                      the Jetson Linux root: the L4T packages (including nvidia-l4t-multimedia, which
+#                                       holds libnvv4l2), the Multimedia API and, for the SIPL backend, the SIPL API
+#   <root>/arm-gnu-toolchain-*/         Arm's aarch64-none-linux-gnu toolchain
+#   <root>/orin-aarch64.cmake           a CMake toolchain file naming both
+# `syntax` also needs clang, and the yaml-cpp sources that a first `build` fetches into <root>/build-streamer.
+#
+#   cross_build.sh syntax   type-check every source against the Orin headers (clang, no linking)
+#   cross_build.sh build    configure and build the aarch64 argus_sender (extra arguments go to cmake)
+
+set -euo pipefail
+
+mode="${1:-build}"
+shift || true
+project_dir="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+root="${ORIN_CROSS_ROOT:-${HOME}/github/orin-cross-39.2.1}"
+sysroot="${root}/sysroot"
+mmapi="${sysroot}/usr/src/jetson_multimedia_api"
+toolchain="${root}/orin-aarch64.cmake"
+
+for path in "${sysroot}" "${mmapi}/argus/include" "${toolchain}" "${sysroot}/usr/lib/aarch64-linux-gnu/nvidia/libnvv4l2.so"; do
+    if [[ ! -e "${path}" ]]; then
+        echo "error: ${path} is missing; see the header of this script" >&2
+        exit 1
+    fi
+done
+
+case "${mode}" in
+syntax)
+    cxx_include="$(ls -d "${root}"/arm-gnu-toolchain*/aarch64-none-linux-gnu/include/c++/* | head -n1)"
+    yaml_include="${root}/build-streamer/_deps/yaml_cpp-src/include"
+    if [[ ! -d "${yaml_include}" ]]; then
+        echo "error: ${yaml_include} is missing; run 'cross_build.sh build' once to fetch yaml-cpp" >&2
+        exit 1
+    fi
+    status=0
+    for source in "${project_dir}"/src/*.cpp; do
+        # The SIPL headers need C++17; the rest of the sender is C++14.
+        standard=c++14
+        [[ "${source}" == */SiplCapture.cpp ]] && standard=c++17
+        clang++ --target=aarch64-linux-gnu --sysroot="${sysroot}" -std="${standard}" -fsyntax-only -Wno-everything \
+            -I"${sysroot}/usr/src/jetson_sipl_api/sipl/include" -I"${sysroot}/usr/src/jetson_sipl_api/sipl/include/nvsci" -I"${sysroot}/usr/src/jetson_sipl_api/sipl/include/query/include" \
+            -DNVMMAPI_SUPPORTED -I"${project_dir}/src" -I"${mmapi}/argus/include" -I"${mmapi}/include" \
+            -I"${mmapi}/samples/common/classes" -I/usr/local/cuda/targets/sbsa-linux/include \
+            -I"${sysroot}/usr/include/drm" -I"${yaml_include}" -isystem "${sysroot}/usr/include/aarch64-linux-gnu" \
+            -isystem "${cxx_include}" -isystem "${cxx_include}/aarch64-none-linux-gnu" \
+            "${source}" || status=1
+    done
+    exit "${status}"
+    ;;
+build)
+    build_dir="${root}/build-streamer"
+    cmake -S "${project_dir}" -B "${build_dir}" -DCMAKE_TOOLCHAIN_FILE="${toolchain}" -DCMAKE_BUILD_TYPE=Release \
+        -DDISABLE_MULTIPROCESS=ON -DMMAPI_ROOT="${mmapi}" -DDRM_INCLUDE_DIR="${sysroot}/usr/include/drm" \
+        -DBUILD_TESTING=OFF -DSIPL_ROOT="${sysroot}/usr/src/jetson_sipl_api/sipl" "$@"
+    cmake --build "${build_dir}" --target argus_sender -j "$(nproc)"
+    echo "Built ${build_dir}/argus_sender (aarch64; not run)"
+    ;;
+*)
+    echo "usage: cross_build.sh syntax|build [cmake args]" >&2
+    exit 2
+    ;;
+esac