devel/quickcpplib: fix on 32 bit platforms

128 bit integers are only supported on 64 bit platforms. Test for them
using the correct feature test macro to enable the port there.

Approved by: portmgr (build fix blanket)
MFH: 2023Q4
See also: https://github.com/ned14/quickcpplib/issues/50

(cherry picked from commit 7e25442cf7355486041ebb30c77a7c815aa3e701)