anchor.diff:  FROM alpine:3.7
  +
  +ENV LANG=C.UTF-8
   
   # Here we install GNU libc (aka glibc) and set C.UTF-8 locale as default.
   
  
positive.code:         "$ALPINE_GLIBC_BASE_PACKAGE_FILENAME" \
          "$ALPINE_GLIBC_BIN_PACKAGE_FILENAME" \
          "$ALPINE_GLIBC_I18N_PACKAGE_FILENAME"
  
  ENV LANG=C.UTF-8
  
negative.code:     ALPINE_GLIBC_I18N_PACKAGE_FILENAME="glibc-i18n-$ALPINE_GLIBC_PACKAGE_VERSION.apk" && \
      apk add --no-cache --virtual=.build-dependencies wget ca-certificates && \
      wget \
          "https://raw.githubusercontent.com/sgerrand/alpine-pkg-glibc/master/sgerrand.rsa.pub" \
          -O "/etc/apk/keys/sgerrand.rsa.pub" && \
      wget \
          "$ALPINE_GLIBC_BASE_URL/$ALPINE_GLIBC_PACKAGE_VERSION/$ALPINE_GLIBC_BASE_PACKAGE_FILENAME" \
  