[NaCl SDK] Add realpath(3) implementation.

native_client_sdk/src/libraries/nacl_io/library.dsc

Index: native_client_sdk/src/libraries/nacl_io/library.dsc
diff --git a/native_client_sdk/src/libraries/nacl_io/library.dsc b/native_client_sdk/src/libraries/nacl_io/library.dsc
index 5861e0232cc43e20fc5e3f4952d334bf62d171b1..2403e1d3622d4cbf0bba854b42c7ecdedb80d0dd 100644
--- a/native_client_sdk/src/libraries/nacl_io/library.dsc
+++ b/native_client_sdk/src/libraries/nacl_io/library.dsc
@@ -66,9 +66,9 @@
         "syscalls/bind.c",
         "syscalls/cfgetispeed.c",
         "syscalls/cfgetospeed.c",
-        "syscalls/cfsetspeed.c",
         "syscalls/cfsetispeed.c",
         "syscalls/cfsetospeed.c",
+        "syscalls/cfsetspeed.c",
         "syscalls/chdir.c",
         "syscalls/chmod.c",
         "syscalls/chown.c",
@@ -116,19 +116,13 @@
         "syscalls/pipe.c",
         "syscalls/poll.c",
         "syscalls/readlink.c",
-        "syscalls/rmdir.c",
+        "syscalls/realpath.c",
         "syscalls/recv.c",
         "syscalls/recvfrom.c",
         "syscalls/recvmsg.c",
         "syscalls/remove.c",
         "syscalls/rename.c",
-        "syscalls/tcdrain.c",
-        "syscalls/tcflow.c",
-        "syscalls/tcflush.c",
-        "syscalls/tcgetattr.c",
-        "syscalls/tcsendbreak.c",
-        "syscalls/tcsetattr.c",
-        "syscalls/truncate.c",
+        "syscalls/rmdir.c",
         "syscalls/select.c",
         "syscalls/send.c",
         "syscalls/sendmsg.c",
@@ -149,9 +143,16 @@
         "syscalls/socket.c",
         "syscalls/socketpair.c",
         "syscalls/symlink.c",
-        "syscalls/unlink.c",
+        "syscalls/tcdrain.c",
+        "syscalls/tcflow.c",
+        "syscalls/tcflush.c",
+        "syscalls/tcgetattr.c",
+        "syscalls/tcsendbreak.c",
+        "syscalls/tcsetattr.c",
+        "syscalls/truncate.c",
         "syscalls/umount.c",
         "syscalls/uname.c",
+        "syscalls/unlink.c",
         "syscalls/utime.c",
         "syscalls/utimes.c",
       ],
@@ -238,6 +239,7 @@
         "netinet/tcp.h",
         "netinet6/in6.h",
         "poll.h",
+        "stdlib.h",
         "sys/ioctl.h",
         "sys/mount.h",
         "sys/poll.h",
@@ -258,6 +260,7 @@
         "netinet/tcp.h",
         "netinet6/in6.h",
         "poll.h",
+        "stdlib.h",
         "sys/ioctl.h",
         "sys/mount.h",
         "sys/poll.h",