Move libc replacement files from src/backend/port to src/port.

src/port/memcmp.c

@@ -0,0 +1,36 @@
+/*-------------------------------------------------------------------------
+ *
+ * memcmp.c
+ *	  compares memory bytes
+ *
+ * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  $Header: /cvsroot/pgsql/src/port/memcmp.c,v 1.1 2002/07/18 04:13:59 momjian Exp $
+ *
+ * This file was taken from NetBSD and is used by SunOS because memcmp
+ * on that platform does not properly compare negative bytes.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include <string.h>
+
+/*
+ * Compare memory regions.
+ */
+int
+memcmp(const void *s1, const void *s2, size_t n)
+{
+	if (n != 0) {
+		const unsigned char *p1 = s1, *p2 = s2;
+
+		do {
+			if (*p1++ != *p2++)
+				return (*--p1 - *--p2);
+		} while (--n != 0);
+	}
+	return 0;
+}