message: build_recipe: patch lightstep in the meantime
  Fixes:
  While we wait for
  and then further, for an update to newer lightstep, this fetches an
  absolute path to a patch that lets our lightstep build work on newer gcc
  versions (>= 7).
diff: @@ -7,6 +7,22 @@ VERSION=0.36
  wget -O lightstep-tracer-cpp-$VERSION.tar.gz https://github.com/lightstep/lightstep-tracer-cpp/releases/download/v${VERSION//./_}/lightstep-tracer-cpp-$VERSION.tar.gz
  tar xf lightstep-tracer-cpp-$VERSION.tar.gz
  cd lightstep-tracer-cpp-$VERSION
  +
  +# see https://github.com/lyft/envoy/issues/1387 for progress
  +cat > ../lightstep-missing-header.diff << EOF
  +--- ./src/c++11/lightstep/options.h.bak 2017-08-04 09:30:19.527076744 -0400
  ++++ ./src/c++11/lightstep/options.h 2017-08-04 09:30:33.742106924 -0400
  +@@ -5,6 +5,7 @@
  + // Options for Tracer implementations, starting Spans, and finishing
  + // Spans.
  +
  ++#include <functional>
  + #include <chrono>
  + #include <memory>
  +
  +EOF
  +patch -p0 < ../lightstep-missing-header.diff
  +
  # Added for legacy compatibility, should not be needed in new build recipes.
  [ -z "$PROTOBUF_BUILD" ] && PROTOBUF_BUILD="$THIRDPARTY_BUILD"
  ./configure --disable-grpc --prefix=$THIRDPARTY_BUILD --enable-shared=no \
  