libxshmfence port fails build

[Neil Schroeder]

I think I picked a bad day to go from 10-STABLE to 11-CURRENT then fully
rebuild all my ports...


In file included from xshmfence_alloc.c:27:
In file included from ./xshmfenceint.h:33:
./xshmfence_futex.h:40:39: error: use of undeclared identifier 'INT_MAX'
--- xshmfence_futex.lo ---
In file included from xshmfence_futex.c:27:
In file included from ./xshmfenceint.h:33:
./xshmfence_futex.h:40:39: error: use of undeclared identifier 'INT_MAX'
--- xshmfence_alloc.lo ---
        return sys_futex(addr, UMTX_OP_WAKE, INT_MAX);
                                             ^
--- xshmfence_futex.lo ---
        return sys_futex(addr, UMTX_OP_WAKE, INT_MAX);
                                             ^

I am not too bad with general hackery of dependencies and makefiles but
this I'm not sure how to address.

Any ideas fine people?

NS