Remove duplicated _rand48 implementation. Use stdlib version instead

Originally, there are _rand48 (in libc/bionic/_rand48.c) and __rand48
(in libc/stdlib/_rand48.c) implemented in bionic.  Besides the naming,
the functionality is identical.  This patch removes the duplicated
_rand48.  Also, drand48 and erand48 are modified accordingly.

Change-Id: Ie5761a0a97f45df8538222a77edacb7c3e0125d7
diff --git a/libc/Android.mk b/libc/Android.mk
index e619267..39c63a2 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -220,7 +220,6 @@
 	tzcode/strptime.c \
 	bionic/__errno.c \
 	bionic/__set_errno.c \
-	bionic/_rand48.c \
 	bionic/cpuacct.c \
 	bionic/arc4random.c \
 	bionic/basename.c \
diff --git a/libc/bionic/_rand48.c b/libc/bionic/_rand48.c
deleted file mode 100644
index e422781..0000000
--- a/libc/bionic/_rand48.c
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
- * Copyright (c) 1993 Martin Birgmeier
- * All rights reserved.
- *
- * You may redistribute unmodified or modified versions of this source
- * code provided that the above copyright notice and this and the
- * following conditions are retained.
- *
- * This software is provided ``as is'', and comes with no warranties
- * of any kind. I shall in no event be liable for anything that happens
- * to anyone/anything when using this software.
- */
-
-#include <sys/cdefs.h>
-#include "rand48.h"
-
-unsigned short _rand48_seed[3] = {
-	RAND48_SEED_0,
-	RAND48_SEED_1,
-	RAND48_SEED_2
-};
-unsigned short _rand48_mult[3] = {
-	RAND48_MULT_0,
-	RAND48_MULT_1,
-	RAND48_MULT_2
-};
-unsigned short _rand48_add = RAND48_ADD;
-
-void
-_dorand48(unsigned short xseed[3])
-{
-	unsigned long accu;
-	unsigned short temp[2];
-
-	accu = (unsigned long) _rand48_mult[0] * (unsigned long) xseed[0] +
-	 (unsigned long) _rand48_add;
-	temp[0] = (unsigned short) accu;	/* lower 16 bits */
-	accu >>= sizeof(unsigned short) * 8;
-	accu += (unsigned long) _rand48_mult[0] * (unsigned long) xseed[1] +
-	 (unsigned long) _rand48_mult[1] * (unsigned long) xseed[0];
-	temp[1] = (unsigned short) accu;	/* middle 16 bits */
-	accu >>= sizeof(unsigned short) * 8;
-	accu += _rand48_mult[0] * xseed[2] + _rand48_mult[1] * xseed[1] + _rand48_mult[2] * xseed[0];
-	xseed[0] = temp[0];
-	xseed[1] = temp[1];
-	xseed[2] = (unsigned short) accu;
-}
diff --git a/libc/bionic/drand48.c b/libc/bionic/drand48.c
index fd48196..93272cf 100644
--- a/libc/bionic/drand48.c
+++ b/libc/bionic/drand48.c
@@ -15,10 +15,10 @@
 
 #include "rand48.h"
 
-extern unsigned short _rand48_seed[3];
+extern unsigned short __rand48_seed[3];
 
 double
 drand48(void)
 {
-	return erand48(_rand48_seed);
+	return erand48(__rand48_seed);
 }
diff --git a/libc/bionic/erand48.c b/libc/bionic/erand48.c
index 843ff34..4ecbead 100644
--- a/libc/bionic/erand48.c
+++ b/libc/bionic/erand48.c
@@ -18,7 +18,7 @@
 double
 erand48(unsigned short xseed[3])
 {
-	_dorand48(xseed);
+	__dorand48(xseed);
 	return ldexp((double) xseed[0], -48) +
 	       ldexp((double) xseed[1], -32) +
 	       ldexp((double) xseed[2], -16);
diff --git a/libc/bionic/rand48.h b/libc/bionic/rand48.h
deleted file mode 100644
index 0a3d83d..0000000
--- a/libc/bionic/rand48.h
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * Copyright (c) 1993 Martin Birgmeier
- * All rights reserved.
- *
- * You may redistribute unmodified or modified versions of this source
- * code provided that the above copyright notice and this and the
- * following conditions are retained.
- *
- * This software is provided ``as is'', and comes with no warranties
- * of any kind. I shall in no event be liable for anything that happens
- * to anyone/anything when using this software.
- *
- * $FreeBSD: src/lib/libc/gen/rand48.h,v 1.2 2002/02/01 01:32:19 obrien Exp $
- */
-
-#ifndef _RAND48_H_
-#define _RAND48_H_
-
-#include <math.h>
-#include <stdlib.h>
-
-void		_dorand48(unsigned short[3]);
-
-#define	RAND48_SEED_0	(0x330e)
-#define	RAND48_SEED_1	(0xabcd)
-#define	RAND48_SEED_2	(0x1234)
-#define	RAND48_MULT_0	(0xe66d)
-#define	RAND48_MULT_1	(0xdeec)
-#define	RAND48_MULT_2	(0x0005)
-#define	RAND48_ADD	(0x000b)
-
-#endif /* _RAND48_H_ */