try installing libstdc++ 4

Author: vszakats

_build.sh

@@ -1127,13 +1127,26 @@ build_single_target() {
         # https://packages.debian.org/testing/all/libstdc++-13-dev-arm64-cross/filelist
         # /usr/aarch64-linux-gnu/include/c++/13/
         tmp="$(find "/usr/${_TRIPLETSH}/include/c++" -mindepth 1 -maxdepth 1 -type d | head -n 1 || true)"
-        if [ -z "${tmp}" ]; then
-          >&2 echo '! Error: Failed to detect g++-cross env root.'
-          exit 1
+        if [ -n "${tmp}" ]; then
+          _CXXFLAGS_GLOBAL+=" -I${tmp}"
+          _CXXFLAGS_GLOBAL+=" -I${tmp}/${_TRIPLETSH}"
+          _CXXFLAGS_GLOBAL+=" -I${tmp}/backward"
+        else
+          # https://packages.debian.org/trixie/arm64/libstdc++-12-dev/filelist
+          # /usr/include/c++/12/algorithm
+          # /usr/include/aarch64-linux-gnu/c++/12/ext/opt_random.h
+          tmp1="$(find "/usr/include/c++" -mindepth 1 -maxdepth 1 -type d | head -n 1 || true)"
+          tmp2="$(find "/usr/include/${_TRIPLETSH}/c++" -mindepth 1 -maxdepth 1 -type d | head -n 1 || true)"
+          if [ -n "${tmp1}" ] && \
+             [ -n "${tmp2}" ]; then
+            _CXXFLAGS_GLOBAL+=" -I${tmp1}"
+            _CXXFLAGS_GLOBAL+=" -I${tmp2}"
+            _CXXFLAGS_GLOBAL+=" -I${tmp1}/backward"
+          else
+            >&2 echo '! Error: Failed to detect g++-cross env root.'
+            exit 1
+          fi
         fi
-        _CXXFLAGS_GLOBAL+=" -I${tmp}"
-        _CXXFLAGS_GLOBAL+=" -I${tmp}/${_TRIPLETSH}"
-        _CXXFLAGS_GLOBAL+=" -I${tmp}/backward"
       fi
     fi
 

_ci-linux-debian.sh

@@ -100,6 +100,13 @@ elif [[ "${CW_CONFIG:-}" = *'linux'* ]]; then
       extra+=" libc6-dev-arm64-cross"
     fi
     [[ "${CW_CONFIG:-}" = *'r64'* ]] && extra+=" libc6-dev-riscv64-cross"
+
+    if [ "$(uname -m)" = 'aarch64' ]; then
+      extra+=" libc6-dev-amd64-cross libstdc++${CW_GCCSUFFIX}-dev-amd64-cross"
+    else
+      extra+=" libc6-dev-arm64-cross libstdc++${CW_GCCSUFFIX}-dev-arm64-cross"
+    fi
+    [[ "${CW_CONFIG:-}" = *'r64'* ]] && extra+=" libc6-dev-riscv64-cross libstdc++${CW_GCCSUFFIX}-dev-riscv64-cross"
   fi
   if [[ "${CW_CONFIG:-}" = *'boringssl'* ]] || [[ "${CW_CONFIG:-}" = *'awslc'* ]]; then
     if [ "$(uname -m)" = 'aarch64' ]; then