daemon: GC remove-unused-links phase uses 'statx' when available.

* config-daemon.ac: Check for 'statx'.
* nix/libstore/gc.cc (LocalStore::removeUnusedLinks) [HAVE_STATX]: Use
'statx' instead of 'lstat'.

1 files changed, 2 insertions, 1 deletions

diff --git a/config-daemon.ac b/config-daemon.ac
index 848e1e58da1..50ead355a81 100644
--- a/config-daemon.ac
+++ b/config-daemon.ac
@@ -91,8 +91,9 @@ if test "x$guix_build_daemon" = "xyes"; then
   dnl sched_setaffinity: to improve RPC locality.
   dnl statvfs: to detect disk-full conditions.
   dnl strsignal: for error reporting.
+  dnl statx: fine-grain 'stat' call, new in glibc 2.28.
   AC_CHECK_FUNCS([lutimes lchown posix_fallocate sched_setaffinity \
-     statvfs nanosleep strsignal])
+     statvfs nanosleep strsignal statx])
 
   dnl Check whether the store optimiser can optimise symlinks.
   AC_MSG_CHECKING([whether it is possible to create a link to a symlink])