IWD check in download

[Mitch]

Valid iwd: test/gob_aim.iwd
clientDownload: 0 : begining "test/gob_aim.iwd"
clientDownload: 0 : file "test/gob_aim.iwd" completed
Not a valid iwd: test/server.cfg

		void SV_BeginDownload_f( int a1 ) {
    char * file = Cmd_Argv(1);
    int len;

    if((len = strlen(file)) > 3 && !strcmp(file + len - 4, ".iwd"))
    {
        printf("Valid iwd: %s\n", file);
        typedef int (*SV_BeginDownload_f_t)(int a1);
        SV_BeginDownload_f_t SV_BeginDownload_f = (SV_BeginDownload_f_t)0x0808E508;
        SV_BeginDownload_f(a1);
    }
    else
        printf("Not a valid iwd: %s\n", file);
}

#if COD_VERSION == COD2_1_0
    int * addressToDownloadPointer = (int *)0x0815D584;
    *addressToDownloadPointer = (int)SV_BeginDownload_f;
#endif 
	

		typedef char * (*Cmd_Argv_t)(int arg);
#if COD_VERSION == COD2_1_0
    static Cmd_Argv_t Cmd_Argv = (Cmd_Argv_t)0x0806001C;
#elif COD_VERSION == COD2_1_2
    static Cmd_Argv_t Cmd_Argv = (Cmd_Argv_t)0x08060228;
#elif COD_VERSION == COD2_1_3
    static Cmd_Argv_t Cmd_Argv = (Cmd_Argv_t)0x08060220;
#else
    #warning static Cmd_Argv_t Cmd_Argv = (Cmd_Argv_t)NULL;
    static Cmd_Argv_t Cmd_Argv = (Cmd_Argv_t)NULL;
#endif 
	

https://github.com/M-itch/libcod/com...9ef0a8cb70d2c1
http://znation.nl/libcod