2 files changed, 12 insertions, 0 deletions

diff --git a/m4/getopt.m4 b/m4/getopt.m4
index ac3b38e385e..3ebc7b7edf5 100644
--- a/m4/getopt.m4
+++ b/m4/getopt.m4
@@ -32,7 +32,16 @@ AC_DEFUN([gl_FUNC_GETOPT_POSIX],
 # getopt_long_only.
 AC_DEFUN([gl_FUNC_GETOPT_GNU],
 [
+  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.
   m4_divert_text([INIT_PREPARE], [gl_getopt_required=GNU])
+
+  dnl No need to invoke gl_FUNC_GETOPT_POSIX here; this is automatically
+  dnl done through the module dependency getopt-gnu -> getopt-posix.
 ])
 
 # Determine whether to replace the entire getopt facility.
diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4
index bfac944ea05..030304d6777 100644
--- a/m4/gnulib-comp.m4
+++ b/m4/gnulib-comp.m4
@@ -259,6 +259,9 @@ AC_DEFUN([gl_INIT],
   fi
   gl_STDLIB_MODULE_INDICATOR([getloadavg])
   gl_FUNC_GETOPT_GNU
+  dnl Because of the way gl_FUNC_GETOPT_GNU is implemented (the gl_getopt_required
+  dnl mechanism), there is no need to do any AC_LIBOBJ or AC_SUBST here; they are
+  dnl done in the getopt-posix module.
   gl_FUNC_GETOPT_POSIX
   if test $REPLACE_GETOPT = 1; then
     AC_LIBOBJ([getopt])