Fix preprocessor directives checking TARGET_OS_TV

[bazuchan]

My xcode has /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/TargetConditionals.h containing

// Make sure all TARGET_OS_* and TARGET_CPU_* values are defined

#ifndef TARGET_OS_TV
    #define TARGET_OS_TV         0
#endif

[heiher]

cc @yiguous

[yiguous]

I think this PR is better for compiling HevSocks5Tunnel on Apple platform.
Actually, hev_exec_run and daemon will not be used when developing app for Apple's OS, including AppleTVOS.
So just making compiling finished on Apple platform is totally OK.

[heiher]

Thanks.