diff --git a/package/tor/tor.mk b/package/tor/tor.mk
index f6d3b7fe25..a4643913df 100644
--- a/package/tor/tor.mk
+++ b/package/tor/tor.mk
@@ -32,6 +32,7 @@ else
 TOR_CONF_OPTS += --disable-seccomp
 endif
 
+# uses gnu extensions
 TOR_CONF_ENV = ac_cv_prog_cc_c99='-std=gnu99'
 
 $(eval $(autotools-package))