Move headers from server/include to include/maxscale

- Headers now to be included as <maxscale/xyz.h>
- First step, no cleanup of headers has been made. Only moving
  from one place to another + necessary modifications.

include/maxscale/rdtsc.h

@@ -0,0 +1,56 @@
+#ifndef _RDTSC_H
+#define _RDTSC_H
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl.
+ *
+ * Change Date: 2019-07-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+/**
+ * @file rdtsc.h Access the process time-stamp counter
+ *
+ * This is an Intel only facilty that is used to access an accurate time
+ * value, the granularity of which is related to the processor clock speed
+ * and the overhead for access is much lower than using any system call
+ * mechanism.
+ *
+ *
+ * @verbatim
+ * Revision History
+ *
+ * Date         Who             Description
+ * 19/09/2014   Mark Riddoch    Initial implementation
+ *
+ * @endverbatim
+ */
+
+typedef unsigned long long CYCLES;
+
+/**
+ * Get the current time-stamp counter value from the processor. This is the
+ * count of CPU cyceles as a 64 bit value.
+ *
+ * The value returned is related to the clock speed, to obtian a value in
+ * seconds divide the returned value by the clock frequency for the processor.
+ *
+ * Note, on multi-processsor systems care much be taken to avoid the thread
+ * moving to a different processor when taken succsive value of RDTSC to
+ * obtian accurate timing. This may be done by setting pocessor affinity for
+ * the thread. See sched_setaffinity/sched_getaffinity.
+ *
+ * @return CPU cycle count
+ */
+static __inline__ CYCLES rdtsc(void)
+{
+    unsigned long long int x;
+    __asm__ volatile (".byte 0x0f, 0x31" : "=A" (x));
+    return x;
+}
+#endif