Make libnosys function stubs part of libnacl

src/untrusted/nacl/stubs/popen.c

Index: src/untrusted/nacl/stubs/popen.c
diff --git a/src/untrusted/nosys/popen.c b/src/untrusted/nacl/stubs/popen.c
similarity index 82%
rename from src/untrusted/nosys/popen.c
rename to src/untrusted/nacl/stubs/popen.c
index 8083bbf2e71fe490439ad5de68c8d46632690a8f..7bcf10627314fd99202b097a4384c7030ebdc7e4 100644
--- a/src/untrusted/nosys/popen.c
+++ b/src/untrusted/nacl/stubs/popen.c
@@ -15,6 +15,3 @@ FILE *popen(const char *command, const char *modes) {
   errno = ENOSYS;
   return NULL;
 }
-
-#include "native_client/src/untrusted/nosys/warning.h"
-stub_warning(popen);