Access .data section in Position Independent Code

I'm building a shared library with NASM. In that library, in some function, I need what we'd call a static variable in C. Basically, I think it is some space in the .data section:

    SECTION .data
last_tok:       dq 0 ; Define a QWORD

The problem arises when I try to access last_tok in my function.

I read the NASM Manual: 8.2 Writing Linux/ELF Shared Libraries which explains the problem and gives the solution.

    SECTION .data
last_tok:              dq 0     ; Define a QWORD

    SECTION .text
    EXTERN _GLOBAL_OFFSET_TABLE_
    GLOBAL strtok:function
strtok:
    enter    0, 0
    push     rbx
    call     .get_GOT
.get_GOT:
    pop      rbx
    add      rbx, _GLOBAL_OFFSET_TABLE_ + $$ - .get_GOT wrt ..gotpc

    mov      [rbx + last_tok wrt ..gotoff], rdi ; Store the contents of RDI at last_tok

    mov      rbx, [rbp - 8]
    leave
    ret

It may work with ELF32, but with ELF64 I get the following error:

nasm -f elf64  -o strtok.o strtok.s
strtok:15: error: ELF64 requires ..gotoff references to be qword
<builtin>: recipe for target 'strtok.o' failed
make: *** [strtok.o] Error 1

What am I doing wrong?