+ dnl Set the variable gl_getopt_required, so that all invocations of
+ dnl gl_GETOPT_CHECK_HEADERS in the scope of the current configure file
+ dnl will check for getopt with GNU extensions.
+ dnl This means that if one gnulib-tool invocation requests getopt-posix
+ dnl and another gnulib-tool invocation requests getopt-gnu, it is as if
+ dnl both had requested getopt-gnu.