perf: build binary packages

Dockerfile

@@ -1,11 +1,15 @@
 FROM ksmanis/stage3:20230807@sha256:9b65a62d87c5a5d2074b5efb2baa3907337e3e4d39a6771cfa3963257055a45e AS distcc-builder
+COPY --from=ksmanis/gentoo-distcc:tcp /var/cache/binpkgs /var/cache/binpkgs
 RUN --mount=type=bind,from=ksmanis/portage,source=/var/db/repos/gentoo,target=/var/db/repos/gentoo,rw \
     set -eux; \
     emerge --sync; \
     emerge --info; \
-    emerge --quiet-build -tv distcc; \
-    rm -rf /var/cache/distfiles/; \
-    distcc --version
+    emerge --quiet-build -bktv distcc gentoolkit; \
+    distcc --version; \
+    find /var/cache/distfiles/ -mindepth 1 -delete -print; \
+    eclean packages; \
+    emerge --deselect gentoolkit; \
+    CLEAN_DELAY=0 emerge --depclean gentoolkit
 
 FROM distcc-builder AS distcc-tcp
 ARG TARGETPLATFORM