Remove unnecessary base dependencies that bloat layer size

This change reduces the layer for this `RUN` command from 1GB to 678MB
as shown in the `docker history <image name>` output.

image/base/Dockerfile

@@ -25,6 +25,14 @@ RUN gpg --import /tmp/nginx_public_keys.key &&\
     rm /tmp/nginx_public_keys.key &&\
     /tmp/install-nginx
 
+FROM builder AS thpfoff_builder
+
+# This tool allows us to disable huge page support for our current process
+# since the flag is preserved through forks and execs it can be used on any
+# process
+ADD thpoff.c /src/thpoff.c
+RUN gcc -o /usr/local/sbin/thpoff /src/thpoff.c && rm /src/thpoff.c
+
 FROM discourse/ruby:3.3.6-${DEBIAN_RELEASE}-slim AS discourse_dependencies
 
 ARG DEBIAN_RELEASE
@@ -51,14 +59,14 @@ RUN --mount=type=tmpfs,target=/var/log \
     echo "debconf debconf/frontend select Teletype" | debconf-set-selections; \
     apt-get -y update && DEBIAN_FRONTEND=noninteractive apt-get -y install gnupg sudo curl fping locales \
     ca-certificates rsync \
-    cmake g++ pkg-config patch \
-    libxslt-dev libcurl4-openssl-dev \
-    libssl-dev libyaml-dev libtool \
+    patch \
+    libcurl4-openssl-dev \
+    libssl-dev libyaml-dev \
     libpcre3 libpcre3-dev zlib1g zlib1g-dev \
-    libxml2-dev gawk parallel \
+    gawk \
     libreadline-dev anacron wget \
     psmisc whois brotli libunwind-dev \
-    libtcmalloc-minimal4 cmake \
+    libtcmalloc-minimal4 \
     pngcrush pngquant ripgrep poppler-utils \
 # imagemagick runtime dependencies
     libheif1 libjbig0 libtiff6 libpng16-16 libfontconfig1 \
@@ -133,11 +141,7 @@ RUN gem install pups --force &&\
     mkdir -p /pups/bin/ &&\
     ln -s /usr/local/bin/pups /pups/bin/pups
 
-# This tool allows us to disable huge page support for our current process
-# since the flag is preserved through forks and execs it can be used on any
-# process
-ADD thpoff.c /src/thpoff.c
-RUN gcc -o /usr/local/sbin/thpoff /src/thpoff.c && rm /src/thpoff.c
+COPY --from=thpfoff_builder /usr/local/sbin/thpoff /usr/local/sbin/thpoff
 
 # clean up for docker squash
 RUN rm -fr /usr/local/share/doc &&\
@@ -162,16 +166,23 @@ RUN install -dm 0755 -o discourse -g discourse /var/www/discourse &&\
     sudo -u discourse git clone --branch $DISCOURSE_BRANCH --filter=tree:0 https://github.com/discourse/discourse.git /var/www/discourse &&\
     gem install bundler --conservative -v $(awk '/BUNDLED WITH/ { getline; gsub(/ /,""); print $0 }' /var/www/discourse/Gemfile.lock)
 
-FROM discourse_slim AS discourse_release
-ENV RAILS_ENV=production
+FROM discourse_slim AS discourse_bundle_dependencies
 
-RUN cd /var/www/discourse &&\
+RUN apt update &&\
+    apt install -y cmake g++ &&\
+    cd /var/www/discourse &&\
     sudo -u discourse bundle config --local deployment true &&\
     sudo -u discourse bundle config --local path ./vendor/bundle &&\
     sudo -u discourse bundle config --local without test development &&\
     sudo -u discourse bundle install --jobs $(($(nproc) - 1)) &&\
     find /var/www/discourse/vendor/bundle -name cache -not -path '*/gems/*' -type d -exec rm -rf {} + &&\
     find /var/www/discourse/vendor/bundle -name tmp -type d -exec rm -rf {} +
 
+FROM discourse_slim AS discourse_release
+ENV RAILS_ENV=production
+
+COPY --from=discourse_bundle_dependencies /var/www/discourse/vendor/bundle /var/www/discourse/vendor/bundle
+COPY --from=discourse_bundle_dependencies /home/discourse/.bundle /home/discourse/.bundle
+
 RUN cd /var/www/discourse &&\
     sudo -u discourse /bin/bash -c 'if [ -f yarn.lock ]; then yarn install --frozen-lockfile && yarn cache clean; else pnpm install --frozen-lockfile; fi'