ffi/posix: fix typo in cdecls

[benoit-pierre]

This change is 

[NiLuJe]

(The actual constant definition was okay, so this is just to avoid mishaps on future regens).

[benoit-pierre]

Yeah, except we can't really regen from ffi-cdecl/posix_decl.c which is how that discrepancy got in. ;(

[benoit-pierre]

I have not investigated, but I get this error:

ffi-cdecl/posix_decl.c:331:1: error: ...-pc-linux-gnu-debug/staging/share/lua/5.1//gcc/cdecl.lua:30: attempt to call method 'value' (a nil value)
stack traceback:
        ...-pc-linux-gnu-debug/staging/share/lua/5.1//gcc/cdecl.lua:30: in function 'format_attributes'
        ...-pc-linux-gnu-debug/staging/share/lua/5.1//gcc/cdecl.lua:266: in function 'format_node_class'
        ...-pc-linux-gnu-debug/staging/share/lua/5.1//gcc/cdecl.lua:354: in function 'format'
        ...4-pc-linux-gnu-debug/staging/share/lua/5.1/ffi-cdecl.lua:71: in function <...4-pc-linux-gnu-debug/staging/share/lua/5.1/ffi-cdecl.lua:45>
  331 | cdecl_func(htons)
      | ^~~~~~~~~~

But not if I comment the cdecl_func(fopen) line…

[NiLuJe]

Yeah, I recall it being pissy about something, unless a chunk of it was commented out :/.

It never really made much sense to me either (but it did work at one point, so not sure whether it got broken by newer glibcs, or by newer GCCs...).

Been happening for quite a while, though.