Repro for https://github.com/sparklemotion/nokogiri/pull/1731#issuecomment-399350729

Dockerfile

FROM gcr.io/google-appengine/ruby:latest

ARG REQUESTED_RUBY_VERSION="2.5.1"

RUN if test -n "$REQUESTED_RUBY_VERSION" -a \
        ! -x /rbenv/versions/$REQUESTED_RUBY_VERSION/bin/ruby; then \
      (apt-get update -y \
        && apt-get install -y -q gcp-ruby-$REQUESTED_RUBY_VERSION) \
      || (cd /rbenv/plugins/ruby-build \
        && git pull \
        && RUBY_CONFIGURE_OPTS=--with-jemalloc rbenv install -s $REQUESTED_RUBY_VERSION) \
      && rbenv global $REQUESTED_RUBY_VERSION \
      && gem install -q --no-rdoc --no-ri bundler --version $BUNDLER_VERSION \
      && apt-get clean \
      && rm -f /var/lib/apt/lists/*_*; \
    fi
ENV RBENV_VERSION=${REQUESTED_RUBY_VERSION:-$RBENV_VERSION}

ENV NOKOGIRI_USE_SYSTEM_LIBRARIES=1

COPY . /app/

RUN date; \
    if test -f Gemfile.lock; then \
      case "$RAILS_ENV" in \
        (production) \
          bundle install --without="development test" ;; \
        (*) \
          bundle install -- ;; \
      esac \
      && rbenv rehash; \
    fi

Gemfile

source 'https://rubygems.org'

gem 'nokogiri', '1.8.3'

Gemfile.lock

GEM
  remote: https://rubygems.org/
  specs:
    mini_portile2 (2.3.0)
    nokogiri (1.8.3)
      mini_portile2 (~> 2.3.0)

PLATFORMS
  ruby

DEPENDENCIES
  nokogiri (= 1.8.3)

BUNDLED WITH
   1.16.1