--- old/common/autoconf/basics.m4	2016-09-13 07:53:23.702937067 -0400
+++ new/common/autoconf/basics.m4	2016-09-13 07:53:23.238910735 -0400
@@ -662,6 +662,11 @@
       [SYSROOT=$with_sysroot]
   )
 
+  AC_ARG_WITH(build_sysroot, [AS_HELP_STRING([--with-build-sysroot],
+      [use this directory as build_sysroot])],
+      [BUILD_SYSROOT=$with_build_sysroot]
+  )
+
   AC_ARG_WITH([tools-dir], [AS_HELP_STRING([--with-tools-dir],
       [alias for --with-toolchain-path for backwards compatibility])],
       [BASIC_PREPEND_TO_PATH([TOOLCHAIN_PATH],$with_tools_dir)]