library: rename 'diskstat' source as 'diskstats' files

Where possible, libprocps files convey the name of the
actual source pseudo file under the '/proc' directory.

This brings diskstats into line with such an approach.

Signed-off-by: Jim Warner <james.warner@comcast.net>

proc/diskstats.h

@@ -0,0 +1,70 @@
+/*
+ * diskstat - Disk statistics - part of procps
+ *
+ * Copyright (c) 2003 Fabian Frederick
+ * Copyright (C) 2003 Albert Cahalan
+ * Copyright (C) 2015 Craig Small <csmall@enc.com.au>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#ifndef PROC_DISKSTAT_H
+#define PROC_DISKSTAT_H
+
+#include <sys/cdefs.h>
+
+__BEGIN_DECLS
+
+enum procps_diskstat_devitem {
+    PROCPS_DISKSTAT_READS,
+    PROCPS_DISKSTAT_READS_MERGED,
+    PROCPS_DISKSTAT_READ_SECTORS,
+    PROCPS_DISKSTAT_READ_TIME,
+    PROCPS_DISKSTAT_WRITES,
+    PROCPS_DISKSTAT_WRITES_MERGED,
+    PROCPS_DISKSTAT_WRITE_SECTORS,
+    PROCPS_DISKSTAT_WRITE_TIME,
+    PROCPS_DISKSTAT_IO_INPROGRESS,
+    PROCPS_DISKSTAT_IO_TIME,
+    PROCPS_DISKSTAT_IO_WTIME
+};
+
+struct procps_diskstat;
+struct procps_diskstat_dev;
+
+int procps_diskstat_new (struct procps_diskstat **info);
+int procps_diskstat_read (struct procps_diskstat *info);
+
+int procps_diskstat_ref (struct procps_diskstat *info);
+int procps_diskstat_unref (struct procps_diskstat **info);
+
+int procps_diskstat_dev_count (const struct procps_diskstat *info);
+int procps_diskstat_dev_getbyname(
+        const struct procps_diskstat *info,
+        const char *name);
+
+unsigned long procps_diskstat_dev_get(
+        const struct procps_diskstat *info,
+        const enum procps_diskstat_devitem item,
+        const unsigned int devid);
+
+char* procps_diskstat_dev_getname(
+        const struct procps_diskstat *info,
+        const unsigned int devid);
+
+int procps_diskstat_dev_isdisk(
+        const struct procps_diskstat *info,
+        const unsigned int devid);
+__END_DECLS
+#endif