RE: [lwip-devel] [task #7142] Sanity check user-configurable values

[Goldschmidt Simon]

> in tcp.h:
> 
> #if TCP_WND > 0xffff
> #error TCP_WND must fit in an u16_t
> #endif
> 
> in etharp.h:
> 
> #if ARP_TABLE_SIZE > 0x7f
> #error ARP_TABLE_SIZE must fit in an s8_t #endif

Since those are directly related to the type of the array, I'd suggest
to leave them near the declaration. If someday the declaration type is
changed, it's more likely the test is also changed if it's directly
above the declaration...