--- gcc/configure.orig	2019-11-29 16:01:46.850423000 -0800
+++ gcc/configure	2019-11-29 16:05:09.818243000 -0800
@@ -3673,7 +3673,9 @@ if test x${gcc_gxx_include_dir} = x; then
   fi
 elif test "${with_sysroot+set}" = set; then
   gcc_gxx_without_sysroot=`expr "${gcc_gxx_include_dir}" : "${with_sysroot}"'\(.*\)'`
-  if test "${gcc_gxx_without_sysroot}"; then
+  if test "${with_sysroot}" = "/"; then
+    gcc_gxx_include_dir_add_sysroot=1
+  elif test "${gcc_gxx_without_sysroot}"; then
     gcc_gxx_include_dir="${gcc_gxx_without_sysroot}"
     gcc_gxx_include_dir_add_sysroot=1
   fi