[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 4676004438eb01b45bb62287e201c0cdea64339e..a56cb64cedb8645e57de95e52bfb808108aaa35f 100644
--- a/native_client_sdk/src/libraries/nacl_io/library.dsc
+++ b/native_client_sdk/src/libraries/nacl_io/library.dsc
@@ -68,9 +68,9 @@
         "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",
@@ -118,19 +118,13 @@
         "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",
@@ -151,9 +145,16 @@
         "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",
       ],
@@ -241,6 +242,7 @@
         "netinet/tcp.h",
         "netinet6/in6.h",
         "poll.h",
+        "stdlib.h",
         "sys/ioctl.h",
         "sys/mount.h",
         "sys/poll.h",
@@ -261,6 +263,7 @@
         "netinet/tcp.h",
         "netinet6/in6.h",
         "poll.h",
+        "stdlib.h",
         "sys/ioctl.h",
         "sys/mount.h",
         "sys/poll.h",