2004-12-03  Stepan Kasal  <kasal@ucw.cz>

	Add a specialized check for resolv.h.  Thanks to Gerrit P. Haase,
	Reini Urban and Paul Eggert for reporting the dependencies.

	* lib/autoconf/headers.m4 (AC_HEADER_RESOLV): New macro.
	* doc/autoconf.texi (AC_HEADER_RESOLV): Document it.
	(AC_HEADER_STAT): @cvindex{STAT_MACROS_BROKEN}, not @acindex.

Index: doc/autoconf.texi
===================================================================
RCS file: /cvsroot/autoconf/autoconf/doc/autoconf.texi,v
retrieving revision 1.846
diff -u -r1.846 autoconf.texi
--- doc/autoconf.texi	29 Nov 2004 21:43:11 -0000	1.846
+++ doc/autoconf.texi	3 Dec 2004 09:43:08 -0000
@@ -4750,10 +4750,34 @@
 @code{MAJOR_IN_SYSMACROS}.
 @end defmac
 
+@defmac AC_HEADER_RESOLV
+@acindex{HEADER_RESOLV}
+@cvindex HAVE_RESOLV_H
+@hdrindex{resolv.h}
+Checks for header @file{resolv.h}, checking for prerequisities first.
+To properly use @file{resolv.h}, your code should contain something like
+the following:
+
+@verbatim
+#if HAVE_SYS_TYPES_H
+#  include <sys/types.h>
+#endif
+#ifdef HAVE_NETINET_IN_H
+#  include <netinet/in.h>   /* inet_ functions / structs */
+#endif
+#ifdef HAVE_ARPA_NAMESER_H
+#  include <arpa/nameser.h> /* DNS HEADER struct */
+#endif
+#ifdef HAVE_NETDB_H
+#  include <netdb.h>
+#endif
+#include <resolv.h>
+@end verbatim
+@end defmac
 
 @defmac AC_HEADER_STAT
 @acindex{HEADER_STAT}
-@acindex{STAT_MACROS_BROKEN}
+@cvindex STAT_MACROS_BROKEN
 @hdrindex{sys/stat.h}
 If the macros @code{S_ISDIR}, @code{S_ISREG}, etc.@: defined in
 @file{sys/stat.h} do not work properly (returning false positives),
Index: lib/autoconf/headers.m4
===================================================================
RCS file: /cvsroot/autoconf/autoconf/lib/autoconf/headers.m4,v
retrieving revision 1.41
diff -u -r1.41 headers.m4
--- lib/autoconf/headers.m4	1 Jun 2004 05:33:28 -0000	1.41
+++ lib/autoconf/headers.m4	3 Dec 2004 09:43:08 -0000
@@ -440,6 +440,32 @@
 ])# AC_HEADER_MAJOR
 
 
+# AC_HEADER_RESOLV
+# ----------------
+# According to http://www.mcsr.olemiss.edu/cgi-bin/man-cgi?resolver+3,
+# sys/types.h, netinet/in.h and arpa/nameser.h are required on IRIX.
+# netinet/in.h is needed on Cygwin, too.
+# With Solaris 9, netdb.h is required, to get symbols like HOST_NOT_FOUND.
+#
+AN_HEADER(resolv.h,	[AC_HEADER_RESOLV])
+AC_DEFUN([AC_HEADER_RESOLV],
+[AC_CHECK_HEADERS(sys/types.h netinet/in.h arpa/nameser.h netdb.h resolv.h,
+		  [], [],
+[[#if HAVE_SYS_TYPES_H
+#  include <sys/types.h>
+#endif
+#ifdef HAVE_NETINET_IN_H
+#  include <netinet/in.h>   /* inet_ functions / structs */
+#endif
+#ifdef HAVE_ARPA_NAMESER_H
+#  include <arpa/nameser.h> /* DNS HEADER struct */
+#endif
+#ifdef HAVE_NETDB_H
+#  include <netdb.h>
+#endif]])
+])# AC_HEADER_RESOLV
+
+
 # AC_HEADER_STAT
 # --------------
 # FIXME: Shouldn't this be named AC_HEADER_SYS_STAT?