acl platform code: fix acl set return type (1.0-maint)

borg/platform_darwin.pyx

@@ -10,7 +10,7 @@ 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

borg/platform_freebsd.pyx

@@ -19,7 +19,7 @@ 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

borg/platform_linux.pyx

@@ -17,7 +17,7 @@ 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)