Compile toolbox's newfs_msdos for the host

For potential use with build/make/tools/fat16copy.py

Bug: 63035155
Test: mmma system/core/toolbox; newfs_msdos
Change-Id: I8ad50b8c181fc4ec21e191ec9fea8e9aa11d2d9b

toolbox/Android.bp

@@ -61,3 +61,10 @@ cc_binary {
     defaults: ["toolbox_defaults"],
     srcs: ["r.c"],
 }
+
+cc_binary_host {
+    name: "newfs_msdos",
+    defaults: ["toolbox_defaults"],
+    srcs: ["newfs_msdos.c"],
+    cflags: ["-Dnewfs_msdos_main=main"]
+}

toolbox/newfs_msdos.c

@@ -32,15 +32,17 @@ static const char rcsid[] =
 
 #include <sys/param.h>
 
-#ifndef ANDROID
+#ifdef __APPLE__
+#elif defined(ANDROID)
+#include <linux/fs.h>
+#include <linux/hdreg.h>
+#include <stdarg.h>
+#include <sys/ioctl.h>
+#else
 #include <sys/fdcio.h>
 #include <sys/disk.h>
 #include <sys/disklabel.h>
 #include <sys/mount.h>
-#else
-#include <stdarg.h>
-#include <linux/fs.h>
-#include <linux/hdreg.h>
 #endif
 
 #include <sys/stat.h>
@@ -58,6 +60,10 @@ static const char rcsid[] =
 #include <time.h>
 #include <unistd.h>
 
+#ifndef __unused
+#define __unused __attribute__((__unused__))
+#endif
+
 #define MAXU16   0xffff     /* maximum unsigned 16-bit quantity */
 #define BPN      4          /* bits per nibble */
 #define NPB      2          /* nibbles per byte */
@@ -794,7 +800,10 @@ static void getstdfmt(const char *fmt, struct bpb *bpb)
  * Get disk slice, partition, and geometry information.
  */
 
-#ifdef ANDROID
+#ifdef __APPLE__
+static void getdiskinfo(__unused int fd, __unused const char* fname, __unused const char* dtype,
+                        __unused int oflag, __unused struct bpb* bpb) {}
+#elif ANDROID
 static void getdiskinfo(int fd, const char *fname, const char *dtype,
                         __unused int oflag,struct bpb *bpb)
 {