error: ‘TH_SYN’ undeclared despite <netinet/tcp.h> being included
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I am getting these error messages:

    error: ‘TH_SYN’ undeclared (first use in this function)
    error: ‘TH_ACK’ undeclared (first use in this function)

I Have included `<netinet/tcp.h>` and used `grep -r TH_SYN ./*` in `usr/include` to check if TH_SYN and TH_ACK are defined, and they are. Yet I get the above error. 

`<netinet/tcp.h>` is not included to late in the code either, so I'm a bit stumped. Why won't it compile? I'm using backtrack5 and gcc, if that is of any importance. There's also a gap between # and define in `<netinet/tcp.h>` but that shouldn't matter should it?