Provides some of the missing POSIX file syscalls

src/trusted/desc/nacl_desc_imc.c

Index: src/trusted/desc/nacl_desc_imc.c
diff --git a/src/trusted/desc/nacl_desc_imc.c b/src/trusted/desc/nacl_desc_imc.c
index 6433c68187e7dced0adb602eaebf80b28d3c0547..4f9fcc8966167278487cd004b09650bd4f7e0bec 100644
--- a/src/trusted/desc/nacl_desc_imc.c
+++ b/src/trusted/desc/nacl_desc_imc.c
@@ -388,6 +388,11 @@ static struct NaClDescVtbl const kNaClDescImcConnectedDescVtbl = {
   NaClDescPWriteNotImplemented,
   NaClDescIoctlNotImplemented,
   NaClDescFstatNotImplemented,
+  NaClDescFchdirNotImplemented,
+  NaClDescFchmodNotImplemented,
+  NaClDescFsyncNotImplemented,
+  NaClDescFdatasyncNotImplemented,
+  NaClDescFtruncateNotImplemented,
   NaClDescGetdentsNotImplemented,
   NaClDescExternalizeSizeNotImplemented,
   NaClDescExternalizeNotImplemented,
@@ -428,6 +433,11 @@ static struct NaClDescVtbl const kNaClDescImcDescVtbl = {
   NaClDescPWriteNotImplemented,
   NaClDescIoctlNotImplemented,
   NaClDescImcDescFstat,  /* diff */
+  NaClDescFchdirNotImplemented,
+  NaClDescFchmodNotImplemented,
+  NaClDescFsyncNotImplemented,
+  NaClDescFdatasyncNotImplemented,
+  NaClDescFtruncateNotImplemented,
   NaClDescGetdentsNotImplemented,
   NaClDescExternalizeSizeNotImplemented,
   NaClDescExternalizeNotImplemented,
@@ -468,6 +478,11 @@ static struct NaClDescVtbl const kNaClDescXferableDataDescVtbl = {
   NaClDescPWriteNotImplemented,
   NaClDescIoctlNotImplemented,
   NaClDescXferableDataDescFstat,  /* diff */
+  NaClDescFchdirNotImplemented,
+  NaClDescFchmodNotImplemented,
+  NaClDescFsyncNotImplemented,
+  NaClDescFdatasyncNotImplemented,
+  NaClDescFtruncateNotImplemented,
   NaClDescGetdentsNotImplemented,
   NaClDescXferableDataDescExternalizeSize,  /* diff */
   NaClDescXferableDataDescExternalize,  /* diff */