message: guix: Supply --keep-failed for debugging
diff: @@ -150,6 +150,7 @@ time-machine() {
  guix time-machine --url=https://github.com/dongcarl/guix.git \
  --commit=b066c25026f21fb57677aa34692a5034338e7ee3 \
  --max-jobs="$MAX_JOBS" \
  + --keep-failed \
  ${SUBSTITUTE_URLS:+--substitute-urls="$SUBSTITUTE_URLS"} \
  ${ADDITIONAL_GUIX_COMMON_FLAGS} ${ADDITIONAL_GUIX_TIMEMACHINE_FLAGS} \
  -- "$@"
  @@ -259,6 +260,12 @@ EOF
  # make the downloaded depends sources available to it. The sources
  # should have been downloaded prior to this invocation.
  #
  + # --keep-failed keep build tree of failed builds
  + #
  + # When builds of the Guix environment itself (not Bitcoin Core)
  + # fail, it is useful for the build tree to be kept for debugging
  + # purposes.
  + #
  # ${SUBSTITUTE_URLS:+--substitute-urls="$SUBSTITUTE_URLS"}
  #
  # fetch substitute from SUBSTITUTE_URLS if they are
  @@ -281,6 +288,7 @@ EOF
  ${SOURCES_PATH:+--share="$SOURCES_PATH"} \
  ${BASE_CACHE:+--share="$BASE_CACHE"} \
  --max-jobs="$MAX_JOBS" \
  + --keep-failed \
  ${SUBSTITUTE_URLS:+--substitute-urls="$SUBSTITUTE_URLS"} \
  ${ADDITIONAL_GUIX_COMMON_FLAGS} ${ADDITIONAL_GUIX_ENVIRONMENT_FLAGS} \
  -- env HOST="$host" \
  