[NaCl SDK] nacl_io: handle null irt function pointers

native_client_sdk/src/libraries/nacl_io/kernel_wrap_bionic.cc

Index: native_client_sdk/src/libraries/nacl_io/kernel_wrap_bionic.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_wrap_bionic.cc b/native_client_sdk/src/libraries/nacl_io/kernel_wrap_bionic.cc
index 7bdf4f9862e29f4d03cbd011ed95cc1f87ae8152..621e0bd5e922efbe9aaa09698d6c6f16c3c00d32 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_wrap_bionic.cc
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_wrap_bionic.cc
@@ -338,13 +338,11 @@ static void assign_real_pointers() {
 }
 
 #define CHECK_REAL(func) \
-  if (!REAL(func))       \
-    assign_real_pointers();
-
-#define CHECK_REAL_NOSYS(func)  \
-  CHECK_REAL(func)              \
-  if (!REAL(func))              \
-    return ENOSYS;
+  if (!REAL(func)) {          \
+    assign_real_pointers();   \
+    if (!REAL(func))          \
+      return ENOSYS;          \
+  }
 
 // "real" functions, i.e. the unwrapped original functions.
 
@@ -436,7 +434,7 @@ int _real_lseek(int fd, int64_t offset, int whence, int64_t* new_offset) {
 
 int _real_lstat(const char* path, struct stat* buf) {
   struct nacl_abi_stat st;
-  CHECK_REAL(fstat);
+  CHECK_REAL(lstat);
 
   int err = REAL(lstat)(path, (struct stat*)&st);
   if (err) {
@@ -504,7 +502,7 @@ int _real_write(int fd, const void* buf, size_t count, size_t* nwrote) {
 }
 
 int _real_getcwd(char* pathname, size_t len) {
-  CHECK_REAL_NOSYS(getcwd);
+  CHECK_REAL(getcwd);
   return REAL(getcwd)(pathname, len);
 }