[Bug c++/87380] Explicit instantations should use weak symbols on darwin

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87380

--- Comment #6 from Iain Sandoe <iains at gcc dot gnu.org> ---
hmm...

Linux:
$ more lib.s 
        .file   "lib.cc"
        .text
        .weak   _ZN1AIiE6memberE
        .section       
.bss._ZN1AIiE6memberE,"awG",@nobits,_ZN1AIiE6memberE,comdat
        .align 4
        .type   _ZN1AIiE6memberE, @gnu_unique_object
        .size   _ZN1AIiE6memberE, 4

Darwin:
$ more lib.s
        .text
        .globl __ZN1AIiE6memberE
        .zerofill __DATA,__pu_bss2,__ZN1AIiE6memberE,4,2
        .text

so... now to figure out why.