acl platform code: fix acl set return type (1.1-maint)

src/borg/platform/darwin.pyx

@@ -13,7 +13,7 @@ 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

src/borg/platform/freebsd.pyx

@@ -22,7 +22,7 @@ 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

src/borg/platform/linux.pyx

@@ -26,7 +26,7 @@ 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)