diff --git a/tools/bazel b/tools/bazel
index 6f5230c..37eb774 100755
--- a/tools/bazel
+++ b/tools/bazel
@@ -100,7 +100,6 @@
 ENVIRONMENT_VARIABLES+=(USER="${USER}")
 ENVIRONMENT_VARIABLES+=(PATH="/usr/bin:/bin")
 ENVIRONMENT_VARIABLES+=(HOME="${HOME}")
-ENVIRONMENT_VARIABLES+=(LOGNAME="${LOGNAME}")
 ENVIRONMENT_VARIABLES+=(TERM="${TERM}")
 ENVIRONMENT_VARIABLES+=(LANG="${LANG:-C}")
 
@@ -108,6 +107,10 @@
   ENVIRONMENT_VARIABLES+=(DISPLAY="${DISPLAY}")
 fi
 
+if [[ ! -z "${LOGNAME+x}" ]]; then
+    ENVIRONMENT_VARIABLES+=(LOGNAME="${LOGNAME}")
+fi
+
 if [[ -x "${VERSION_BAZEL}-real" ]]; then
   exec -a "${VERSION_BAZEL}" env -i \
       "${ENVIRONMENT_VARIABLES[@]}" \