Fixed compilation errors on Linux.

[sbzappa]

I fixed some errors I encountered while compiling snes9x-emunwa on Linux.
I did not test this yet with Bsnes-plus, but I'm guessing they would have the same error if type SOCKET has never been defined for *nix.

I also did the following on the main branch snes9x-nwaccess:

--- a/emu-nwaccess/snes9x-nwaccess.cpp
+++ b/emu-nwaccess/snes9x-nwaccess.cpp
@@ -33,10 +33,6 @@
 #define INVALID_SOCKET -1
 #define SOCKET_ERROR -1
 #define closesocket(s) close(s)
-typedef int SOCKET;
-typedef struct sockaddr_in SOCKADDR_IN;
-typedef struct sockaddr SOCKADDR;
-typedef struct in_addr IN_ADDR;