--- a/src/gcc/configure.ac
+++ b/src/gcc/configure.ac
@@ -149,7 +149,9 @@
 if test "${with_sysroot+set}" = set; then
   gcc_gxx_without_sysroot=`expr "${gcc_gxx_include_dir}" : "${with_sysroot}"'\(.*\)'`
   if test "${gcc_gxx_without_sysroot}"; then
-    gcc_gxx_include_dir="${gcc_gxx_without_sysroot}"
+    if test x${with_sysroot} != x/; then
+      gcc_gxx_include_dir="${gcc_gxx_without_sysroot}"
+    fi
     gcc_gxx_include_dir_add_sysroot=1
   fi
 fi