diff --git a/src/borg/platform/darwin.pyx b/src/borg/platform/darwin.pyx
index 7a4480e2a..4c3995c1e 100644
--- a/src/borg/platform/darwin.pyx
+++ b/src/borg/platform/darwin.pyx
@@ -12,7 +12,7 @@ cdef extern from "sys/acl.h":
 
     int acl_free(void *obj)
     acl_t acl_get_link_np(const char *path, int type)
-    acl_t acl_set_link_np(const char *path, int type, acl_t acl)
+    int acl_set_link_np(const char *path, int type, acl_t acl)
     acl_t acl_from_text(const char *buf)
     char *acl_to_text(acl_t acl, ssize_t *len_p)
     int ACL_TYPE_EXTENDED
diff --git a/src/borg/platform/freebsd.pyx b/src/borg/platform/freebsd.pyx
index eabc3ace4..8e8ec3f2c 100644
--- a/src/borg/platform/freebsd.pyx
+++ b/src/borg/platform/freebsd.pyx
@@ -21,7 +21,7 @@ cdef extern from "sys/acl.h":
 
     int acl_free(void *obj)
     acl_t acl_get_link_np(const char *path, int type)
-    acl_t acl_set_link_np(const char *path, int type, acl_t acl)
+    int acl_set_link_np(const char *path, int type, acl_t acl)
     acl_t acl_from_text(const char *buf)
     char *acl_to_text_np(acl_t acl, ssize_t *len, int flags)
     int ACL_TEXT_NUMERIC_IDS
diff --git a/src/borg/platform/linux.pyx b/src/borg/platform/linux.pyx
index e820d4b89..ba2348b3a 100644
--- a/src/borg/platform/linux.pyx
+++ b/src/borg/platform/linux.pyx
@@ -25,7 +25,7 @@ cdef extern from "sys/acl.h":
 
     int acl_free(void *obj)
     acl_t acl_get_file(const char *path, int type)
-    acl_t acl_set_file(const char *path, int type, acl_t acl)
+    int acl_set_file(const char *path, int type, acl_t acl)
     acl_t acl_from_text(const char *buf)
     char *acl_to_text(acl_t acl, ssize_t *len)