build: daemon: Add missing feature tests.

* config-daemon.ac: Add feature tests needed for the daemon code.  Taken
  from Nix's `configure.ac'.

config-daemon.ac

@@ -59,6 +59,38 @@ if test "x$guix_build_daemon" = "xyes"; then
 
   CFLAGS="$save_CFLAGS"
   LDFLAGS="$save_LDFLAGS"
+
+  dnl Chroot support.
+  AC_CHECK_FUNCS([chroot unshare])
+  AC_CHECK_HEADERS([sched.h sys/param.h sys/mount.h])
+
+  dnl Check for lutimes, optionally used for changing the mtime of
+  dnl symlinks.
+  AC_CHECK_FUNCS([lutimes])
+
+  dnl Check whether the store optimiser can optimise symlinks.
+  AC_MSG_CHECKING([whether it is possible to create a link to a symlink])
+  ln -s bla tmp_link
+  if ln tmp_link tmp_link2 2> /dev/null; then
+      AC_MSG_RESULT(yes)
+      AC_DEFINE(CAN_LINK_SYMLINK, 1, [Whether link() works on symlinks.])
+  else
+      AC_MSG_RESULT(no)
+  fi
+  rm -f tmp_link tmp_link2
+
+  dnl Check for <locale>.
+  AC_LANG_PUSH(C++)
+  AC_CHECK_HEADERS([locale])
+  AC_LANG_POP(C++)
+
+
+  dnl Check whether we have the `personality' syscall, which allows us
+  dnl to do i686-linux builds on x86_64-linux machines.
+  AC_CHECK_HEADERS([sys/personality.h])
+
+  dnl Check for <linux/fs.h> (for immutable file support).
+  AC_CHECK_HEADERS([linux/fs.h])
 fi
 
 AM_CONDITIONAL([BUILD_DAEMON], [test "x$guix_build_daemon" = "xyes"])