fix(build): compile SatDump with baseline x86-64 to avoid AVX2 crashes (#185)

On x86_64, explicitly pass -march=x86-64 so the compiler emits only
baseline instructions. SatDump's SIMD plugins still compile with their
own per-target flags and do runtime CPU detection, so AVX2 acceleration
remains available on capable hardware. ARM builds are unaffected.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Dockerfile

@@ -130,7 +130,10 @@ RUN cd /tmp \
     && git clone --depth 1 --branch 1.2.2 https://github.com/SatDump/SatDump.git \
     && cd SatDump \
     && mkdir build && cd build \
-    && cmake -DCMAKE_BUILD_TYPE=Release -DBUILD_GUI=OFF -DCMAKE_INSTALL_LIBDIR=lib .. \
+    && ARCH_FLAGS=""; if [ "$(uname -m)" = "x86_64" ]; then ARCH_FLAGS="-march=x86-64"; fi \
+    && cmake -DCMAKE_BUILD_TYPE=Release -DBUILD_GUI=OFF -DCMAKE_INSTALL_LIBDIR=lib \
+           -DCMAKE_C_FLAGS="$ARCH_FLAGS" \
+           -DCMAKE_CXX_FLAGS="$ARCH_FLAGS" .. \
     && make -j$(nproc) \
     && make install \
     && ldconfig \

setup.sh

@@ -957,8 +957,14 @@ install_satdump_from_source_debian() {
     ) &
     progress_pid=$!
 
+    local arch_flags=""
+    if [[ "$(uname -m)" == "x86_64" ]]; then
+      arch_flags="-march=x86-64"
+    fi
+
     if cmake -DCMAKE_BUILD_TYPE=Release -DBUILD_GUI=OFF -DCMAKE_INSTALL_LIBDIR=lib \
-        -DCMAKE_CXX_FLAGS="-Wno-template-body" .. >"$build_log" 2>&1 \
+        -DCMAKE_C_FLAGS="$arch_flags" \
+        -DCMAKE_CXX_FLAGS="$arch_flags -Wno-template-body" .. >"$build_log" 2>&1 \
         && make -j "$(nproc)" >>"$build_log" 2>&1; then
       kill $progress_pid 2>/dev/null; wait $progress_pid 2>/dev/null
       $SUDO make install >/dev/null 2>&1