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

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

.global remainderl
.type remainderl,@function
remainderl:
        fldt 24(%rsp)
        fldt 8(%rsp)
1:      fprem1
        fstsw %ax
        sahf
        jp 1b
        fstp %st(1)
        ret