rework langinfo code for ABI compat and for use by time code

[musl] / src / math / x86_64 / fmodl.s

.global fmodl
.type fmodl,@function
fmodl:
        fldt 24(%rsp)
        fldt 8(%rsp)
1:      fprem
        fstsw %ax
        sahf
        jp 1b
        fstp %st(1)
        ret