1 files changed, 2 insertions, 0 deletions
diff --git a/common.mk b/common.mk
index ed24bbd69c..e73b72d1a2 100644
--- a/common.mk
+++ b/common.mk
@@ -1096,6 +1096,8 @@ update-gems: PHONY
 	    -e 'Downloader::RubyGems.download(gem)' \
 	    bundled_gems
 
+### set the following environment variable or uncomment the line if
+### the Unicode data files are updated every minuites.
 # ALWAYS_UPDATE_UNICODE = yes
 
 UNICODE_FILES = $(srcdir)/enc/unicode/data/UnicodeData.txt \