[build] update Boost to 1.69 and remove RTTI

scripts/update-boost.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+
+set -eu
+
+pushd "$BOOST"
+if [ ! -f dist/bin/bcp ]; then
+    # Build bcp
+    ./bootstrap.sh
+    ./b2 tools/bcp
+fi
+popd
+
+# Extract boost modules that we need
+rm -rf vendor/boost/include
+mkdir -p vendor/boost/include
+"$BOOST/dist/bin/bcp" --boost="$BOOST" --scan $(find {src,include,test,platform,bin} -name "*.cpp" -o -name "*.hpp") vendor/boost/include
+
+pushd vendor/boost
+VERSION=$(sed -n 's/^#define BOOST_LIB_VERSION "\([^"]*\)"$/\1/p' include/boost/version.hpp)
+echo "libboost ${VERSION/_/.} for Mapbox GL Native" > README.md
+git add README.md include
+popd
+
+echo "If everything works, run:"
+echo ""
+echo "    git -C vendor/boost checkout master"
+echo "    git -C vendor/boost commit -m \"update boost to ${VERSION/_/.}\""
+echo "    git -C vendor/boost push"
+echo "    git add vendor/boost"
+echo ""
+echo "and commit."