Add optional pytz dependency to `INSTALL.txt`.

diff --git a/INSTALL.txt b/INSTALL.txt
index 89209f8f9607ac138f0604dc3bea05ff10fcc5eb..32154dcb9ea4a0db149677599a4c9fcb87183708 100644 (file)
--- a/INSTALL.txt
+++ b/INSTALL.txt
@@ -6,6 +6,7 @@ Prerequisites
 
  * Python 2.3 or later (2.4 or later is recommended)
  * Optional: setuptools 0.6b1 or later
+ * Optional: pytz (strongly recommended for real time-zone support)
 
 
 Installation