HP-UX fails to declare if_nametoindex as extern "C". Added a declaration

for it with correct linkage to avoid a linker error.


[SVN r40549]

libs/asio

@@ -1 +1 @@
-Subproject commit d306f9dafe6eb8c60dae9427fec3350e1bdf10a3
+Subproject commit 2ded97148e32eedeac65a9f2c5f37006a854360d