[libc-commits] [libc] [libc] Add limits.h header. (PR #78887)

[Nick Desaulniers via libc-commits]

nickdesaulniers wrote:

```
/usr/include/limits.h:145:17: error: missing binary operator before token "("
```
on my system, that file and line 145 use `__GLIBC_USE`.  There's a comment block at the top of that file that says
```
The GNU C Library is distributed
```
and later has:
```
/* Get the compiler's limits.h, which defines almost all the ISO constants.
# include_next <limits.h>
```
so it seems what's happening is that we have code (somewhere) that is including `<limits.h>` and getting the glibc header.

Perhaps we need an `#include_next <limits.h>` under some very specific conditions.

https://github.com/llvm/llvm-project/pull/78887