libc: centralize a few numeric symbols

[brooks]

Summary

fabs, infinity, and nan are universally implemented so declare them
in gen/Symbol.map.

We would also include __flt_rounds for some reason it's under FBSD_1.3
on arm so until that's gone we're stuck with it. Likewise, everyone but
i386 implements g[gs]etmask.

[imp]

We would also include __flt_rounds for some reason it's under FBSD_1.3 on arm so until that's gone we're stuck with it.

I think that's the result of the OABI -> EABI migration... But it may just be random "didn't do it quite right at the time and we're just now noticing" too. arm binaries from that era were super fragile because we played the tier 2/3 card way too often.

[andrew]

In D42618#972475, @imp wrote:

We would also include __flt_rounds for some reason it's under FBSD_1.3 on arm so until that's gone we're stuck with it.

I think that's the result of the OABI -> EABI migration... But it may just be random "didn't do it quite right at the time and we're just now noticing" too. arm binaries from that era were super fragile because we played the tier 2/3 card way too often.

It's from rG061103347c34bf6e495abadc864ad48bcbf85fe6

[imp]

In D42618#972498, @andrew wrote:

In D42618#972475, @imp wrote:

We would also include __flt_rounds for some reason it's under FBSD_1.3 on arm so until that's gone we're stuck with it.

I think that's the result of the OABI -> EABI migration... But it may just be random "didn't do it quite right at the time and we're just now noticing" too. arm binaries from that era were super fragile because we played the tier 2/3 card way too often.

It's from rG061103347c34bf6e495abadc864ad48bcbf85fe6

ah, that's too late to be the EABI thing then.