Incremental default includes (Was: Modernizing the handling of headers)

[Akim Demaille]

| Index: ChangeLog
| from  Akim Demaille  <address@hidden>
| 
|       * acheaders.m4 (AC_CHECK_HEADER, AC_CHECK_HEADERS): Support $4 =
|       INCLUDES.

This is the next step.

I'm applying it, because it needs to be tested but real people.
Please, note that there is something *very* new happening here: we no
longer check whether a single header (belonging to the default
headers) exists, rather, if it can be included after the one before
it.  That's because of the 4th arg to AC_CHECK_HEADERS in
_AC_INCLUDES_DEFAULT_REQUIREMENTS.

The next step is to spread the use of the default includes in the
other macros.  This time, I won't apply, but I'll ask for comments
first.

Index: ChangeLog
from  Akim Demaille  <address@hidden>
        * acgeneral.m4 (_AC_INCLUDES_DEFAULT_REQUIREMENTS): Guard
        sys/types.h and sys/stat.h, and check for them.

Index: NEWS
===================================================================
RCS file: /cvs/autoconf/NEWS,v
retrieving revision 1.153
diff -u -u -r1.153 NEWS
--- NEWS 2001/06/13 07:51:09 1.153
+++ NEWS 2001/06/13 08:06:51
@@ -1,6 +1,7 @@
 * Major changes in Autoconf 2.50a                       -*- outline -*-
 ** Default includes
-Now include stdint.h.
+- Now include stdint.h.
+- sys/types.h and sys/stat.h are guarded.
 
 ** Bug fixes
 - Mostly in the test suite.
@@ -8,6 +9,8 @@
 - configure accepts --prefix='' again.
 - AC_CHECK_LIB works properly when its first argument is not a
   literal.
+- HAVE_INTTYPES_H is defined only if not conflicting with previous
+  headers.
 
 ** Generic macros
 - AC_CHECK_HEADER and AC_CHECK_HEADERS support a fourth argument to
Index: acgeneral.m4
===================================================================
RCS file: /cvs/autoconf/acgeneral.m4,v
retrieving revision 1.732
diff -u -u -r1.732 acgeneral.m4
--- acgeneral.m4 2001/06/12 14:46:13 1.732
+++ acgeneral.m4 2001/06/13 08:06:52
@@ -2180,8 +2180,12 @@
 dnl If ever you change this variable, please keep autoconf.texi in sync.
 ac_includes_default="\
 #include <stdio.h>
-#include <sys/types.h>
-#include <sys/stat.h>
+#if HAVE_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+#if HAVE_SYS_STAT_H
+# include <sys/stat.h>
+#endif
 #if STDC_HEADERS
 # include <stdlib.h>
 # include <stddef.h>
@@ -2212,7 +2216,9 @@
 #endif"
 ])dnl
 AC_REQUIRE([AC_HEADER_STDC])dnl
-AC_CHECK_HEADERS(stdlib.h string.h memory.h strings.h inttypes.h stdint.h 
unistd.h)
+AC_CHECK_HEADERS([sys/types.h sys/stat.h stdlib.h string.h memory.h strings.h
+                  inttypes.h stdint.h unistd.h],
+                 [], [], $ac_includes_default)
 ])
 
 
Index: doc/autoconf.texi
===================================================================
RCS file: /cvs/autoconf/doc/autoconf.texi,v
retrieving revision 1.464
diff -u -u -r1.464 autoconf.texi
--- doc/autoconf.texi 2001/06/13 07:51:09 1.464
+++ doc/autoconf.texi 2001/06/13 08:07:00
@@ -2778,8 +2778,12 @@
 @example
 @group
 #include <stdio.h>
-#include <sys/types.h>
-#include <sys/stat.h>
+#if HAVE_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+#if HAVE_SYS_STAT_H
+# include <sys/stat.h>
+#endif
 #if STDC_HEADERS
 # include <stdlib.h>
 # include <stddef.h>
Index: tests/atspecific.m4
===================================================================
RCS file: /cvs/autoconf/tests/atspecific.m4,v
retrieving revision 1.44
diff -u -u -r1.44 atspecific.m4
--- tests/atspecific.m4 2001/05/31 08:24:01 1.44
+++ tests/atspecific.m4 2001/06/13 08:07:00
@@ -98,7 +98,8 @@
 # AT_CHECK_HEADER is a better name, but too close from AC_CHECK_HEADER.
 m4_define([AT_CHECK_DEFINES],
 [AT_CHECK([[fgrep '#' config.h |
-   egrep -v 'STDC_HEADERS|STDINT|STDLIB|INTTYPES|MEMORY|STRING|UNISTD']],, 
[$1])])
+ egrep -v 
'STDC_HEADERS|STD(INT|LIB)|INTTYPES|MEMORY|STRING|UNISTD|SYS_(TYPES|STAT)']],,
+          [$1])])
 
 
 # AT_CHECK_AUTOUPDATE