making coreutils configure `gcc -Wall' clean

[Ralf Wildenhues]

The patch below enables CVS coreutils to be built with
  ../coreutils/configure -C CC='gcc -Wall -Werror -fno-builtin' \
                            CPPFLAGS=-Dlint

on my GNU/Linux system, after one more tiny patch to gnulib
(sent to its list).  Not quite sure if that fits your coding style.

Cheers,
Ralf

2006-10-12  Ralf Wildenhues  <address@hidden>

        * configure.ac: Avoid compiler warnings about default return
        type in function definitions and unused variables in tests.
        * src/who.c (print_user) [HAVE_UT_HOST]: hostlen is only needed
        if this is #defined.

Index: configure.ac
===================================================================
RCS file: /cvsroot/coreutils/coreutils/configure.ac,v
retrieving revision 1.89
diff -u -r1.89 configure.ac
--- configure.ac        2 Oct 2006 11:47:48 -0000       1.89
+++ configure.ac        12 Oct 2006 19:40:30 -0000
@@ -58,14 +58,14 @@
 # include <stdlib.h>
 #endif
 extern char **environ;
-unset_TZ ()
+void unset_TZ (void)
 {
   char **from, **to;
   for (to = from = environ; (*to = *from); from++)
     if (! (to[0][0] == 'T' && to[0][1] == 'Z' && to[0][2] == '='))
       to++;
 }
-main()
+int main()
 {
   time_t now = time ((time_t *) 0);
   int hour_GMT0, hour_unset;
@@ -146,7 +146,7 @@
 AC_MSG_CHECKING(ut_host in struct utmp)
 AC_CACHE_VAL(su_cv_func_ut_host_in_utmp,
 [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>
-#include <utmp.h>]], [[struct utmp ut; ut.ut_host;]])],
+#include <utmp.h>]], [[struct utmp ut; return !sizeof ut.ut_host;]])],
   [su_cv_func_ut_host_in_utmp=yes],
   [su_cv_func_ut_host_in_utmp=no])])
 AC_MSG_RESULT($su_cv_func_ut_host_in_utmp)
@@ -159,7 +159,7 @@
   AC_MSG_CHECKING(ut_host in struct utmpx)
   AC_CACHE_VAL(su_cv_func_ut_host_in_utmpx,
   [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <sys/types.h>
-#include <utmpx.h>]], [[struct utmpx ut; ut.ut_host;]])],
+#include <utmpx.h>]], [[struct utmpx ut; return !sizeof ut.ut_host;]])],
     [su_cv_func_ut_host_in_utmpx=yes],
     [su_cv_func_ut_host_in_utmpx=no])])
   AC_MSG_RESULT($su_cv_func_ut_host_in_utmpx)
@@ -201,7 +201,7 @@
 #define _XOPEN_SOURCE
 #endif
 #include <sys/types.h>
-#include <termios.h>]], [[struct termios t; t.c_line;]])],
+#include <termios.h>]], [[struct termios t; return !sizeof t.c_line;]])],
     [su_cv_sys_c_line_in_termios=yes],
     [su_cv_sys_c_line_in_termios=no])])
   AC_MSG_RESULT($su_cv_sys_c_line_in_termios)
Index: src/who.c
===================================================================
RCS file: /cvsroot/coreutils/coreutils/src/who.c,v
retrieving revision 1.114
diff -u -r1.114 who.c
--- src/who.c   12 Sep 2006 23:32:17 -0000      1.114
+++ src/who.c   12 Oct 2006 19:40:30 -0000
@@ -320,7 +320,9 @@
   char mesg;
   char idlestr[IDLESTR_LEN + 1];
   static char *hoststr;
+#if HAVE_UT_HOST
   static size_t hostlen;
+#endif
 
 #define DEV_DIR_WITH_TRAILING_SLASH "/dev/"
 #define DEV_DIR_LEN (sizeof (DEV_DIR_WITH_TRAILING_SLASH) - 1)