sync.c: change ULONG_MAX to UINT32_MAX
sync.c: change ULONG_MAX to UINT32_MAX

The value returned is uint32_t, not unsigned long.  This creates a
warning when compiling on 64-bit machines.

turingstudio/nasm,turingstudio/nasm,Distrotech/nasm,techkey/nasm,projedi/nasm,techkey/nasm,projedi/nasm,letolabs/nasm,letolabs/nasm,letolabs/nasm,Distrotech/nasm,Distrotech/nasm,projedi/nasm,turingstudio/nasm,techkey/nasm,Distrotech/nasm,projedi/nasm,turingstudio/nasm,techkey/nasm,techkey/nasm,projedi/nasm