Fix build on i386

/wrkdirs/usr/ports/x11-toolkits/fox17/work/fox-1.7.62/lib/.libs/libFOX-1.7.so: undefined reference to `__atomic_fetch_add_8'
c++: error: linker command failed with exit code 1 (use -v to see invocation)

• Error code 1

Reported by: pkg-fallout