--- a/m4/ChangeLog
+++ b/m4/ChangeLog
@@ -1,3 +1,13 @@
+2006-04-24  Paul Eggert  <eggert@cs.ucla.edu>
+
+	* unlink-busy.m4 (gl_FUNC_UNLINK_BUSY_TEXT): Use prototype
+	to define main with arguments, for C++.  Reported by Eric Blake.
+	* c-stack.m4 (AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC):
+	Prefer 'int main ()' to 'int main (void)', for C++.
+	* getcwd-path-max.m4 (gl_FUNC_GETCWD_PATH_MAX): Likewise.
+	* fsusage.m4 (gl_FILE_SYSTEM_USAGE): Specify a return type
+	for 'main', for C99 and C++.
+
 2006-04-23  Bruno Haible  <bruno@clisp.org>
 
 	* poll.m4 (gl_FUNC_POLL): Rearrange code, so that POLL_H gets

--- a/m4/c-stack.m4
+++ b/m4/c-stack.m4
@@ -66,7 +66,7 @@
 	 }
 
 	 static int
-	 c_stack_action (void)
+	 c_stack_action ()
 	 {
 	   stack_t st;
 	   struct sigaction act;
@@ -94,7 +94,7 @@
 	 }
 
 	 int
-	 main (void)
+	 main ()
 	 {
 	   #if HAVE_SETRLIMIT && defined RLIMIT_STACK
 	   /* Before starting the endless recursion, try to be friendly

--- a/m4/fsusage.m4
+++ b/m4/fsusage.m4
@@ -1,4 +1,4 @@
-#serial 17
+#serial 18
 # Obtaining file system usage information.
 
 # Copyright (C) 1997, 1998, 2000, 2001, 2003, 2004, 2005, 2006 Free Software
@@ -74,6 +74,7 @@
 #include <sys/param.h>
 #include <sys/types.h>
 #include <sys/mount.h>
+  int
   main ()
   {
     struct statfs fsd;
@@ -106,6 +107,7 @@
 #ifdef HAVE_SYS_VFS_H
 #include <sys/vfs.h>
 #endif
+  int
   main ()
   {
   struct statfs fsd;
@@ -130,6 +132,7 @@
   AC_CACHE_VAL(fu_cv_sys_stat_statfs4,
   [AC_TRY_RUN([#include <sys/types.h>
 #include <sys/statfs.h>
+  int
   main ()
   {
   struct statfs fsd;
@@ -158,6 +161,7 @@
 #ifdef HAVE_SYS_MOUNT_H
 #include <sys/mount.h>
 #endif
+  int
   main ()
   {
   struct statfs fsd;
@@ -190,6 +194,7 @@
 #ifdef HAVE_SYS_FS_TYPES_H
 #include <sys/fs_types.h>
 #endif
+  int
   main ()
   {
   struct fs_data fsd;

--- a/m4/getcwd-path-max.m4
+++ b/m4/getcwd-path-max.m4
@@ -1,4 +1,4 @@
-#serial 10
+#serial 11
 # Check for several getcwd bugs with long file names.
 # If so, arrange to compile the wrapper function.
 
@@ -6,7 +6,7 @@
 # I've heard that this is due to a Linux kernel bug, and that it has
 # been fixed between 2.4.21-pre3 and 2.4.21-pre4.  */
 
-# Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
+# Copyright (C) 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
@@ -61,7 +61,7 @@
 #define BUF_SLOP 20
 
 int
-main (void)
+main ()
 {
 #ifndef PATH_MAX
   /* The Hurd doesn't define this, so getcwd can't exhibit the bug --

--- a/m4/unlink-busy.m4
+++ b/m4/unlink-busy.m4
@@ -1,4 +1,4 @@
-#serial 9
+#serial 10
 
 dnl From J. David Anglin.
 
@@ -18,9 +18,7 @@
         [AC_LANG_SOURCE(
            [AC_INCLUDES_DEFAULT
 	    int
-	    main (argc, argv)
-	      int argc;
-	      char **argv;
+	    main (int argc, char **argv)
 	    {
 	      return !argc || unlink (argv[0]) != 0;
 	    }])],