m4/*_h.m4: improve idioms

[Bruno Haible]

Hi Simon, Eric,

I find it a bit hard to maintain the autoconf macros when a variable initialized
by one .m4 file is assigned in another .m4 file. It's easier if every variable
is only touched in a single .m4 file.

I'm applying this for iconv_h.m4 and m4/wchar.m4. Actually, for iconv_h.m4
this fixes a bug: if gl_REPLACE_ICONV_OPEN happened to expand before
gl_ICONV_H, the final value of ICONV_H was wrong.

Simon, is the part for m4/arpa_inet_h.m4 fine with you? (Not yet committed.)

Bruno


2008-09-27  Bruno Haible  <address@hidden>

        * m4/arpa_inet_h.m4 (gl_REPLACE_ARPA_INET_H): New macro.
        * m4/inet_ntop.m4 (gl_INET_NTOP): Invoke it instead of assigning
        ARPA_INET_H directly.
        * m4/inet_pton.m4 (gl_INET_PTON): Likewise.

        * m4/iconv_h.m4 (gl_REPLACE_ICONV_H): New macro.
        (gl_ICONV_H_DEFAULTS): Initialize ICONV_H here...
        (gl_ICONV_H): Not here.
        * m4/iconv_open.m4 (gl_REPLACE_ICONV_OPEN): Invoke gl_REPLACE_ICONV_H
        instead of assigning ICONV_H directly.

        * m4/wchar.m4 (gl_REPLACE_WCHAR_H): New macro.
        * m4/wcwidth.m4 (gl_FUNC_WCWIDTH): Invoke it instead of assigning
        WCHAR_H directly.

--- m4/arpa_inet_h.m4.orig      2008-09-27 18:54:43.000000000 +0200
+++ m4/arpa_inet_h.m4   2008-09-27 18:45:38.000000000 +0200
@@ -1,4 +1,4 @@
-# arpa_inet_h.m4 serial 4
+# arpa_inet_h.m4 serial 5
 dnl Copyright (C) 2006, 2008 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -25,6 +25,13 @@
   gl_CHECK_NEXT_HEADERS([arpa/inet.h])
 ])
 
+dnl Unconditionally enables the replacement of <arpa/inet.h>.
+AC_DEFUN([gl_REPLACE_ARPA_INET_H],
+[
+  AC_REQUIRE([gl_ARPA_INET_H_DEFAULTS])
+  ARPA_INET_H='arpa/inet.h'
+)
+
 AC_DEFUN([gl_ARPA_INET_MODULE_INDICATOR],
 [
   dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
--- m4/inet_ntop.m4.orig        2008-09-27 18:54:43.000000000 +0200
+++ m4/inet_ntop.m4     2008-09-27 18:45:23.000000000 +0200
@@ -1,4 +1,4 @@
-# inet_ntop.m4 serial 6
+# inet_ntop.m4 serial 7
 dnl Copyright (C) 2005, 2006, 2008 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -9,8 +9,7 @@
   dnl Persuade Solaris <arpa/inet.h> to declare inet_ntop.
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
 
-  AC_REQUIRE([gl_ARPA_INET_H_DEFAULTS])
-  ARPA_INET_H='arpa/inet.h'
+  gl_REPLACE_ARPA_INET_H
 
   AC_REPLACE_FUNCS(inet_ntop)
   gl_PREREQ_INET_NTOP
--- m4/inet_pton.m4.orig        2008-09-27 18:54:43.000000000 +0200
+++ m4/inet_pton.m4     2008-09-27 18:45:28.000000000 +0200
@@ -1,4 +1,4 @@
-# inet_pton.m4 serial 5
+# inet_pton.m4 serial 6
 dnl Copyright (C) 2006, 2008 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -9,8 +9,7 @@
   dnl Persuade Solaris <arpa/inet.h> to declare inet_pton.
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
 
-  AC_REQUIRE([gl_ARPA_INET_H_DEFAULTS])
-  ARPA_INET_H='arpa/inet.h'
+  gl_REPLACE_ARPA_INET_H
 
   AC_REPLACE_FUNCS(inet_pton)
   gl_PREREQ_INET_PTON
--- m4/iconv_h.m4.orig  2008-09-27 18:54:43.000000000 +0200
+++ m4/iconv_h.m4       2008-09-27 18:49:05.000000000 +0200
@@ -1,5 +1,5 @@
-# iconv_h.m4 serial 3
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# iconv_h.m4 serial 4
+dnl Copyright (C) 2007-2008 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.
@@ -8,8 +8,13 @@
 [
   AC_REQUIRE([gl_ICONV_H_DEFAULTS])
   gl_CHECK_NEXT_HEADERS([iconv.h])
-  ICONV_H=
-  AC_SUBST([ICONV_H])
+])
+
+dnl Unconditionally enables the replacement of <iconv.h>.
+AC_DEFUN([gl_REPLACE_ICONV_H],
+[
+  AC_REQUIRE([gl_ICONV_H_DEFAULTS])
+  ICONV_H='iconv.h'
 ])
 
 AC_DEFUN([gl_ICONV_MODULE_INDICATOR],
@@ -25,4 +30,5 @@
   REPLACE_ICONV=0;      AC_SUBST([REPLACE_ICONV])
   REPLACE_ICONV_OPEN=0; AC_SUBST([REPLACE_ICONV_OPEN])
   REPLACE_ICONV_UTF=0;  AC_SUBST([REPLACE_ICONV_UTF])
+  ICONV_H='';           AC_SUBST([ICONV_H])
 ])
--- m4/iconv_open.m4.orig       2008-09-27 18:54:43.000000000 +0200
+++ m4/iconv_open.m4    2008-09-27 18:47:46.000000000 +0200
@@ -1,5 +1,5 @@
-# iconv_open.m4 serial 3
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# iconv_open.m4 serial 4
+dnl Copyright (C) 2007-2008 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.
@@ -38,9 +38,9 @@
 
 AC_DEFUN([gl_REPLACE_ICONV_OPEN],
 [
+  gl_REPLACE_ICONV_H
   REPLACE_ICONV_OPEN=1
   AC_LIBOBJ([iconv_open])
-  ICONV_H='iconv.h'
 ])
 
 AC_DEFUN([gl_FUNC_ICONV_OPEN_UTF],
--- m4/wchar.m4.orig    2008-09-27 18:54:43.000000000 +0200
+++ m4/wchar.m4 2008-09-27 18:51:01.000000000 +0200
@@ -7,7 +7,7 @@
 
 dnl Written by Eric Blake.
 
-# wchar.m4 serial 5
+# wchar.m4 serial 6
 
 AC_DEFUN([gl_WCHAR_H],
 [
@@ -45,6 +45,13 @@
   gl_CHECK_NEXT_HEADERS([wchar.h])
 ])
 
+dnl Unconditionally enables the replacement of <wchar.h>.
+AC_DEFUN([gl_REPLACE_WCHAR_H],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+  WCHAR_H=wchar.h
+])
+
 AC_DEFUN([gl_WCHAR_MODULE_INDICATOR],
 [
   dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
@@ -58,6 +65,5 @@
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_DECL_WCWIDTH=1; AC_SUBST([HAVE_DECL_WCWIDTH])
   REPLACE_WCWIDTH=0;   AC_SUBST([REPLACE_WCWIDTH])
-  WCHAR_H=
-  AC_SUBST([WCHAR_H])
+  WCHAR_H='';          AC_SUBST([WCHAR_H])
 ])
--- m4/wcwidth.m4.orig  2008-09-27 18:54:43.000000000 +0200
+++ m4/wcwidth.m4       2008-09-27 18:50:53.000000000 +0200
@@ -1,5 +1,5 @@
-# wcwidth.m4 serial 13
-dnl Copyright (C) 2006, 2007 Free Software Foundation, Inc.
+# wcwidth.m4 serial 14
+dnl Copyright (C) 2006-2008 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.
@@ -80,6 +80,6 @@
   fi
 
   if test $REPLACE_WCWIDTH = 1 || test $HAVE_DECL_WCWIDTH = 0; then
-    WCHAR_H=wchar.h
+    gl_REPLACE_WCHAR_H
   fi
 ])