anchor.diff:  
   FROM php:$PHP_VERSION-fpm-alpine
   
  -# persistent / runtime deps
  +# build time dependencies
   ENV PHPIZE_DEPS \
       autoconf \
       cmake \
  
positive.code:     make \
      git \
      pkgconf \
      re2c
  
  # inspired by https://github.com/prooph/docker-files/blob/master/php/7.1-fpm
  RUN set -xe \
      && apk add --no-cache --virtual .persistent-deps \
          bash \
          icu-dev \
          libxml2-dev \
          libzip-dev \
          mysql-client \
          gzip
  
  RUN set -xe \
      && apk add --no-cache --virtual .build-deps \
          $PHPIZE_DEPS \
      && docker-php-ext-configure bcmath --enable-bcmath \
      && docker-php-ext-configure intl --enable-intl \
      && docker-php-ext-configure pcntl --enable-pcntl \
      && docker-php-ext-configure pdo_mysql --with-pdo-mysql \
      && docker-php-ext-configure mbstring --enable-mbstring \
  
negative.code:     && docker-php-ext-configure zip --enable-zip --with-libzip \
      && docker-php-ext-install \
          bcmath \
          gd \
          intl \
          pcntl \
          pdo_mysql \
  