--- configure.ac.orig	2005-06-01 18:32:32 +0000
+++ configure.ac	2015-07-27 10:33:56 +0000
@@ -131,10 +131,10 @@
 esac])
 
 if test x${gcc_gxx_include_dir} = x; then
+  topsrcdir=${srcdir}/.. . ${srcdir}/../config.if
   if test x${enable_version_specific_runtime_libs} = xyes; then
-    gcc_gxx_include_dir='${libsubdir}/include/c++'
+    gcc_gxx_include_dir='${libsubdir}/include/'${libstdcxx_incdir_prefix}
   else
-    topsrcdir=${srcdir}/.. . ${srcdir}/../config.if
 changequote(<<, >>)dnl
     gcc_gxx_include_dir="\$(libsubdir)/\$(unlibsubdir)/..\`echo \$(exec_prefix) | sed -e 's|^\$(prefix)||' -e 's|/[^/]*|/..|g'\`/include/"${libstdcxx_incdir}
 changequote([, ])dnl
@@ -648,7 +648,7 @@
   # that we can use it.
   gcc_AC_CHECK_PROG_VER(MAKEINFO, makeinfo, --version,
   [GNU texinfo.* \([0-9][0-9.]*\)],
-  [4.[2-9]*])
+  [4.[1-9]*])
 fi
 
 if test $gcc_cv_prog_makeinfo_modern = no; then