[libgtop] Log error on statvfs failure.

[Robert Roth <robertroth src gnome org>]

commit 3147bf2e34f19e06ae21da768cc318bcc185f530
Author: Robert Roth <robert roth off gmail com>
Date:   Mon Dec 9 01:57:01 2013 +0200

    Log error on statvfs failure.
    
    When doing stat on a FS and failing, log the error message based
    on the errno set to help the user find the reason.
    https://bugzilla.gnome.org/show_bug.cgi?id=685172

 sysdeps/linux/fsusage.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/sysdeps/linux/fsusage.c b/sysdeps/linux/fsusage.c
index b186767..a7fd16c 100644
--- a/sysdeps/linux/fsusage.c
+++ b/sysdeps/linux/fsusage.c
@@ -15,6 +15,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
+#include <errno.h>
 #include <mntent.h>
 
 
@@ -197,7 +198,7 @@ glibtop_get_fsusage_s(glibtop *server, glibtop_fsusage *buf, const char *path)
   memset(buf, 0, sizeof(glibtop_fsusage));
 
   if (statvfs(path, &fsd) < 0) {
-    glibtop_warn_r(server, "statvfs '%s' failed", path);
+    glibtop_warn_r(server, "statvfs '%s' failed: %s", path, strerror (errno));
     return;
   }