diff --git a/release/sysinstall/dist.c b/release/sysinstall/dist.c
index 3596835c9d7d..9a2e489757f5 100644
--- a/release/sysinstall/dist.c
+++ b/release/sysinstall/dist.c
@@ -534,7 +534,7 @@ distExtract(char *parent, Distribution *me)
     /* Make ^C fake a sudden timeout */
     new.sa_handler = handle_intr;
     new.sa_flags = 0;
-    new.sa_mask = 0;
+    (void)sigemptyset(&new.sa_mask);
     sigaction(SIGINT, &new, &old);
 
     /* Loop through to see if we're in our parent's plans */
diff --git a/release/sysinstall/media.c b/release/sysinstall/media.c
index 380b704f48a3..55055ed89576 100644
--- a/release/sysinstall/media.c
+++ b/release/sysinstall/media.c
@@ -677,7 +677,7 @@ mediaExtractDist(char *dir, char *dist, FILE *fp)
     /* Make ^C abort the current transfer rather than the whole show */
     new.sa_handler = handle_intr;
     new.sa_flags = 0;
-    new.sa_mask = 0;
+    (void)sigemptyset(&new.sa_mask);
     sigaction(SIGINT, &new, &old);
 
     while ((i = fread(buf, 1, BUFSIZ, fp)) > 0) {
diff --git a/usr.sbin/sysinstall/dist.c b/usr.sbin/sysinstall/dist.c
index 3596835c9d7d..9a2e489757f5 100644
--- a/usr.sbin/sysinstall/dist.c
+++ b/usr.sbin/sysinstall/dist.c
@@ -534,7 +534,7 @@ distExtract(char *parent, Distribution *me)
     /* Make ^C fake a sudden timeout */
     new.sa_handler = handle_intr;
     new.sa_flags = 0;
-    new.sa_mask = 0;
+    (void)sigemptyset(&new.sa_mask);
     sigaction(SIGINT, &new, &old);
 
     /* Loop through to see if we're in our parent's plans */
diff --git a/usr.sbin/sysinstall/media.c b/usr.sbin/sysinstall/media.c
index 380b704f48a3..55055ed89576 100644
--- a/usr.sbin/sysinstall/media.c
+++ b/usr.sbin/sysinstall/media.c
@@ -677,7 +677,7 @@ mediaExtractDist(char *dir, char *dist, FILE *fp)
     /* Make ^C abort the current transfer rather than the whole show */
     new.sa_handler = handle_intr;
     new.sa_flags = 0;
-    new.sa_mask = 0;
+    (void)sigemptyset(&new.sa_mask);
     sigaction(SIGINT, &new, &old);
 
     while ((i = fread(buf, 1, BUFSIZ, fp)) > 0) {