Pick STLPort endian options when available.

This should be a fix for embedded Visual C++ used with STLPort.

[SVN r65089]

libs/detail

@@ -1 +1 @@
-Subproject commit 0aa7afd1d8a745bcc05be0b212096f000ba2aa4a
+Subproject commit d1a4c127eb04807769dd8379ea69ff752aeca1b8