Fix NaCl regression caused by pepper revision 28.

src/platform-posix.cc

Index: src/platform-posix.cc
diff --git a/src/platform-posix.cc b/src/platform-posix.cc
index bd8a33fabd13e2ec5d65be929e3c4b1fcd5e5a20..9d3d7695f0955b1f84d0b0310dda815909aec726 100644
--- a/src/platform-posix.cc
+++ b/src/platform-posix.cc
@@ -84,7 +84,13 @@ intptr_t OS::CommitPageSize() {
 #ifndef __CYGWIN__
 // Get rid of writable permission on code allocations.
 void OS::ProtectCode(void* address, const size_t size) {
+#if defined(__native_client__)
+  // The Native Client port of V8 uses an interpreter, so
+  // code pages don't need PROT_EXEC.
+  mprotect(address, size, PROT_READ);
+#else
   mprotect(address, size, PROT_READ | PROT_EXEC);
+#endif
 }