https://github.com/kichik/nsis/pull/13
https://sourceforge.net/p/nsis/code/7248/

diff --git a/SConstruct b/SConstruct
index e8252c9..41786f2 100755
--- a/SConstruct
+++ b/SConstruct
@@ -95,8 +95,8 @@ default_doctype = 'html'
 if defenv.WhereIs('hhc', os.environ['PATH']):
 	default_doctype = 'chm'
 
-from time import strftime, gmtime
-cvs_version = strftime('%d-%b-%Y.cvs', gmtime())
+import time
+cvs_version = time.strftime('%d-%b-%Y.cvs', time.gmtime(int(os.environ.get('SOURCE_DATE_EPOCH', time.time()))))
 
 opts = Variables()