diff --git a/src/date.c b/src/date.c
index e94de6013..43e20057c 100644
--- a/src/date.c
+++ b/src/date.c
@@ -38,8 +38,6 @@
 
 #define AUTHORS proper_name ("David MacKenzie")
 
-int putenv ();
-
 static bool show_date (const char *format, struct timespec when);
 
 enum Time_spec
diff --git a/src/env.c b/src/env.c
index 97bec71d4..fb9d7932d 100644
--- a/src/env.c
+++ b/src/env.c
@@ -91,8 +91,6 @@
   proper_name ("Richard Mlynarik"), \
   proper_name ("David MacKenzie")
 
-int putenv ();
-
 extern char **environ;
 
 static struct option const longopts[] =