[Bug bootstrap/80677] LIMITS_H_TEST is wrong

[helmut at subdivi dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80677

Helmut Grohne <helmut at subdivi dot de> changed:

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                 CC|                            |helmut at subdivi dot de

--- Comment #3 from Helmut Grohne <helmut at subdivi dot de> ---
Created attachment 53832
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53832&action=edit
eliminate the need for LIMITS_H_TEST entirely

Rather than fix LIMITS_H_TEST, I now propose deleting it. The check that we try
to perform at build time with wrong paths can be deferred to runtime and then
operated with correct paths. I'm using this patch since at least gcc-11 and
only encountered one regression thus far. It triggers
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80755 on hurd, but this is a plain
gcc bug that needs fixing anyway, so this should be good to go.