diff --git a/contrib/guix/libexec/build.sh b/contrib/guix/libexec/build.sh
index 5097b8b780445..395f885e31316 100644
--- a/contrib/guix/libexec/build.sh
+++ b/contrib/guix/libexec/build.sh
@@ -27,13 +27,17 @@ Required environment variables as seen inside the container:
     DIST_ARCHIVE_BASE: ${DIST_ARCHIVE_BASE:?not set}
     DISTNAME: ${DISTNAME:?not set}
     HOST: ${HOST:?not set}
-    CONFIGFLAGS: ${CONFIGFLAGS:?not set}
     SOURCE_DATE_EPOCH: ${SOURCE_DATE_EPOCH:?not set}
     JOBS: ${JOBS:?not set}
     DISTSRC: ${DISTSRC:?not set}
     OUTDIR: ${OUTDIR:?not set}
 EOF
 
+cat << EOF
+Optional environment variables as seen inside the container:
+    CONFIGFLAGS: ${CONFIGFLAGS}
+EOF
+
 ACTUAL_OUTDIR="${OUTDIR}"
 OUTDIR="${DISTSRC}/output"