[gvfs] build: Fix all statfs() tests failing

[Ondrej Holy <oholy src gnome org>]

commit 66df8f2afbe46e27052f98321c633ccecebbafb1
Author: Bastien Nocera <hadess hadess net>
Date:   Mon Apr 4 10:57:20 2016 +0200

    build: Fix all statfs() tests failing
    
    The current statfs() compilation tests all fail because statfs() expects
    the first argument to be non-null. Pass a dummy path instead of NULL to
    satisfy the compiler.
    
    The patch is taken from GLib, see Bug 764574.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=767331

 configure.ac |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index a6085e1..ddfad4a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -835,7 +835,7 @@ if test "$ac_cv_func_statfs" = yes ; then
   #ifdef HAVE_SYS_STATFS_H
   #include <sys/statfs.h>
   #endif], [struct statfs st;
-  statfs(NULL, &st);],[
+  statfs("/", &st);],[
     AC_MSG_RESULT([2])
     AC_DEFINE(STATFS_ARGS, 2, [Number of arguments to statfs()])],[
     AC_TRY_COMPILE([#include <unistd.h>
@@ -851,7 +851,7 @@ if test "$ac_cv_func_statfs" = yes ; then
   #ifdef HAVE_SYS_STATFS_H
   #include <sys/statfs.h>
   #endif], [struct statfs st;
-  statfs(NULL, &st, sizeof (st), 0);],[
+  statfs("/", &st, sizeof (st), 0);],[
       AC_MSG_RESULT([4])
       AC_DEFINE(STATFS_ARGS, 4, [Number of arguments to statfs()])],[
       AC_MSG_RESULT(unknown)