libc: Sync qsort(3) with FreeBSD revision r318515.

r279663: enhance to handle 32-bit aligned data on 64-bit systems

r279666: qsort(3): small style(9) cleanups.

r288030: Use ANSI C prototypes.  Eliminates -Wold-style-definition
warnings.

r318514: Use size_t.

r318515: Reduce the possible recursion level to log2(N) by always
recursing on the smaller partition instead.

Bug: 38450217
Test: builds, ./tests/run-on-host.sh 64
Change-Id: Ieb622e6f54f8f6d6f62e1bdb491d3b5c8e2f9965
diff --git a/tests/Android.bp b/tests/Android.bp
index a03f1a6..1981457 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -88,6 +88,7 @@
         "nl_types_test.cpp",
         "pthread_test.cpp",
         "pty_test.cpp",
+        "qsort_test.cpp",
         "regex_test.cpp",
         "resolv_test.cpp",
         "sched_test.cpp",
diff --git a/tests/qsort_test.cpp b/tests/qsort_test.cpp
new file mode 100644
index 0000000..95b4789
--- /dev/null
+++ b/tests/qsort_test.cpp
@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdlib.h>
+#include <sys/types.h>
+
+#include <gtest/gtest.h>
+
+#include "gtest_globals.h"
+
+#define BUFFER_SIZE 1024
+
+static int cmp_long(const void *l, const void *r)
+{
+
+  return (*(long *)l - *(long *)r);
+}
+
+static int cmp_int(const void *l, const void *r)
+{
+
+  return (*(int *)l - *(int *)r);
+}
+
+#ifndef arc4random_uniform
+static bool seeded;
+
+u_int32_t arc4random_uniform(uint32_t upper_bound)
+{
+  if (!seeded) {
+    srandom((int)time(NULL));
+    seeded = true;
+  }
+
+  return (random() % upper_bound);
+}
+#endif
+
+TEST(qsort_test, long_test) {
+  long buf[BUFFER_SIZE];
+  long i;
+
+  /* Initialize buffer with known numbers */
+  for (i=0; i<BUFFER_SIZE; i++)
+    buf[i] = i;
+
+  /* Stir 1/4 pairs in the buffer */
+  for (i=0; i<BUFFER_SIZE/4; i++) {
+    u_int32_t pos1, pos2;
+    long t;
+
+    pos1 = arc4random_uniform(BUFFER_SIZE);
+    pos2 = arc4random_uniform(BUFFER_SIZE);
+
+    t = buf[pos1];
+    buf[pos1] = buf[pos2];
+    buf[pos2] = t;
+  }
+
+  /* Sort */
+  qsort(buf, BUFFER_SIZE, sizeof(buf[0]), &cmp_long);
+
+  for (i=0; i<BUFFER_SIZE; i++)
+    EXPECT_EQ(i, buf[i]);
+}
+
+TEST(qsort_test, int_test) {
+  int buf[BUFFER_SIZE];
+  int i;
+
+  /* Initialize buffer with known numbers */
+  for (i=0; i<BUFFER_SIZE; i++)
+    buf[i] = i;
+
+  /* Stir 1/4 pairs in the buffer */
+  for (i=0; i<BUFFER_SIZE/4; i++) {
+    u_int32_t pos1, pos2;
+    int t;
+
+    pos1 = arc4random_uniform(BUFFER_SIZE);
+    pos2 = arc4random_uniform(BUFFER_SIZE);
+
+    t = buf[pos1];
+    buf[pos1] = buf[pos2];
+    buf[pos2] = t;
+  }
+
+  /* Sort */
+  qsort(buf, BUFFER_SIZE, sizeof(buf[0]), &cmp_int);
+
+  for (i=0; i<BUFFER_SIZE; i++)
+    EXPECT_EQ(i, buf[i]);
+}