common/autoconf/basics.m4

*** 660,669 ****
--- 660,674 ----
    AC_ARG_WITH(sysroot, [AS_HELP_STRING([--with-sysroot],
        [use this directory as sysroot])],
        [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)]
    )