load_subtree(): check that `prefix_len` is in the expected range

diff --git a/configure.ac b/configure.ac
index 11d083fbe0efa23eee5e56ccdce3b49effd946be..2f55237e65acfcf9b7fed15ac0386d353eaf0105 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -922,9 +922,9 @@ AC_CACHE_CHECK([whether system succeeds to read fopen'ed directory],
 [
 AC_RUN_IFELSE(
        [AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT],
-               [[char c;
+               [[
                FILE *f = fopen(".", "r");
-               return f && fread(&c, 1, 1, f)]])],
+               return f)]])],
        [ac_cv_fread_reads_directories=no],
        [ac_cv_fread_reads_directories=yes])
 ])