Add a stub for systime-fix, a plugin handling certificate lifetimes gracefully

src/libcharon/Makefile.am

@@ -506,6 +506,13 @@ if MONOLITHIC
 endif
 endif
 
+if USE_SYSTIME_FIX
+  SUBDIRS += plugins/systime_fix
+if MONOLITHIC
+  libcharon_la_LIBADD += plugins/systime_fix/libstrongswan-systime-fix.la
+endif
+endif
+
 if USE_LED
   SUBDIRS += plugins/led
 if MONOLITHIC