Filter out and translate invalid sockopt names.

-Implement GetSockOpt / SetSockOpt
-Fix bug in RecvFrom where sending from localhost
 does not fill in src_addr/src_addr_len on Linux

This partially fixes Etrian Odyssey IV.

Our code did not handle this well, causing random crashes in some
situations.

FIQ has seven banked registers (R8 to R14), not two.

shared appears in the initializer list before mount_point

This allows Fire Emblem to boot again.

This fixes a regression.

Format information is currently only implemented for the ExtSaveData, SharedExtSaveData and SaveData archives, the information is stored in a file alongside the root folder of the archive.

These operations are limited by the open flags specified while opening the file.

Same thing, less code.

Not to say these subscript operators aren't totally ugly as is.