One or two weird linking errors with some inline assembly

I have the following short application (The original is taken from: https://www.aldeid.com/wiki/X86-assembly/Instructions/str) I just modified it (tried to...) to make it compilable on linux too.

#include <stdio.h>

unsigned char mema[4] = {0, 0, 0, 0};

void test4 (void)
{

    asm (
        "str mema\n"
    );

    printf ("\n[+] Test 4: STR\n");
    printf ("STR base: 0x%02x%02x%02x%02x\n", mema[0], mema[1], mema[2], mema[3]);

    if ((mema[0] == 0x00) && (mema[1] == 0x40))
        printf ("Result  : VMware detected\n\n");
    else
        printf ("Result  : Native OS\n\n");
}

int main () {

    test4();
}

and when I try to compile it:

$ gcc -ggdb -O0 -fPIC -x c ./pill.c -o pill                                                                                                       

it gives me the wird error:

/usr/bin/ld: /tmp/ccDhGo05.o: relocation R_X86_64_32S against symbol `mema' can not be used when making a PIE object; recompile with -fPIC
/usr/bin/ld: final link failed: Nonrepresentable section on output
collect2: error: ld returned 1 exit status

However the same thing works on an online compiler: https://gcc.godbolt.org/z/RYWjy8

... except if I move the variable mema to be a local variable in the function test4 when it complains both places about

undefined symbol `mema'

And another weirdity: same stuff works when compiled with clang.

Any idea why this happens? (Not considering the required privilege level for STR, and other thingies, I am just interested in the linking error and why does it work on one system / compiler and not on another.