1 files changed, 22 insertions, 6 deletions

diff --git a/gl/m4/netdb_h.m4 b/gl/m4/netdb_h.m4
index 2c69f999..eb7c3b8b 100644
--- a/gl/m4/netdb_h.m4
+++ b/gl/m4/netdb_h.m4
@@ -1,10 +1,10 @@
-# netdb_h.m4 serial 11
-dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
+# netdb_h.m4 serial 15
+dnl Copyright (C) 2008-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-AC_DEFUN([gl_HEADER_NETDB],
+AC_DEFUN_ONCE([gl_NETDB_H],
 [
   AC_REQUIRE([gl_NETDB_H_DEFAULTS])
   gl_CHECK_NEXT_HEADERS([netdb.h])
@@ -21,18 +21,33 @@ AC_DEFUN([gl_HEADER_NETDB],
     [getaddrinfo freeaddrinfo gai_strerror getnameinfo])
 ])
 
+# gl_NETDB_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_NETDB_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_NETDB_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_NETDB_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_NETDB_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_NETDB_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETADDRINFO])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_NETDB_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_NETDB_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_NETDB_H_DEFAULTS],
 [
-  GNULIB_GETADDRINFO=0; AC_SUBST([GNULIB_GETADDRINFO])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_STRUCT_ADDRINFO=1;   AC_SUBST([HAVE_STRUCT_ADDRINFO])
   HAVE_DECL_FREEADDRINFO=1; AC_SUBST([HAVE_DECL_FREEADDRINFO])
@@ -40,4 +55,5 @@ AC_DEFUN([gl_NETDB_H_DEFAULTS],
   HAVE_DECL_GETADDRINFO=1;  AC_SUBST([HAVE_DECL_GETADDRINFO])
   HAVE_DECL_GETNAMEINFO=1;  AC_SUBST([HAVE_DECL_GETNAMEINFO])
   REPLACE_GAI_STRERROR=0;   AC_SUBST([REPLACE_GAI_STRERROR])
+  REPLACE_GETADDRINFO=0;    AC_SUBST([REPLACE_GETADDRINFO])
 ])