--- a/make/autoconf/toolchain_windows.m4	Sat Sep 14 11:26:26 2019 -0700
+++ b/make/autoconf/toolchain_windows.m4	Sun Sep 15 07:47:13 2019 +0200
@@ -808,7 +808,7 @@
   if test "x$USE_UCRT" = "xtrue"; then
     AC_MSG_CHECKING([for UCRT DLL dir])
     if test "x$with_ucrt_dll_dir" != x; then
-      if test -z "$(ls -d $with_ucrt_dll_dir/*.dll 2> /dev/null)"; then
+      if test -z "$(ls -d "$with_ucrt_dll_dir/"*.dll 2> /dev/null)"; then
         AC_MSG_RESULT([no])
         AC_MSG_ERROR([Could not find any dlls in $with_ucrt_dll_dir])
       else