diff --git a/tool/file2lastrev.rb b/tool/file2lastrev.rb
index 090f2e981d7d0a..44c4318cd88012 100755
--- a/tool/file2lastrev.rb
+++ b/tool/file2lastrev.rb
@@ -75,12 +75,7 @@ def self.output=(output)
           "#define RUBY_LAST_COMMIT_TITLE #{title.dump}"
         end,
         if modified
-          modified.utc.strftime(<<TIME)
-#if defined(RUBY_PATCHLEVEL) && (RUBY_PATCHLEVEL == -1)
-#undef RUBY_RELEASE_DATE
-#define RUBY_RELEASE_DATE "%FT%TZ"
-#endif
-TIME
+          modified.utc.strftime('#define RUBY_RELEASE_DATETIME "%FT%TZ"')
         end,
       ].compact
     }
diff --git a/version.h b/version.h
index 10ab1f607e3038..6d41a35a179670 100644
--- a/version.h
+++ b/version.h
@@ -52,6 +52,9 @@
 #   define RUBY_BRANCH_NAME "trunk"
 #  endif
 #  define RUBY_REVISION_STR " "RUBY_BRANCH_NAME" "RUBY_REVISION
+#  ifndef RUBY_RELEASE_DATETIME
+#   define RUBY_RELEASE_DATETIME RUBY_RELEASE_DATE
+#  endif
 # else
 #  define RUBY_REVISION_STR " revision "RUBY_REVISION
 # endif
@@ -63,7 +66,7 @@
 # define RUBY_DESCRIPTION_WITH(opt) \
     "ruby "RUBY_VERSION		    \
     RUBY_PATCHLEVEL_STR		    \
-    " ("RUBY_RELEASE_DATE	    \
+    " ("RUBY_RELEASE_DATETIME	    \
     RUBY_REVISION_STR")"opt" "	    \
     "["RUBY_PLATFORM"]"
 # define RUBY_COPYRIGHT		    \