[libc-commits] [libc] [libc][math] implement `signbit` (PR #97791)

[via libc-commits]

================
@@ -79,3 +79,13 @@ add_libc_test(
   DEPENDS
     libc.include.llvm-libc-macros.stdckdint_macros
 )
+
+add_libc_test(
----------------
lntue wrote:

Since these function macros are defined by simply using the builtins, you could have some simple tests to make sure the macros are defined like:
```
#ifndef isfinite
#error "isfinite macro is not defined"
#else
assert(isfinite(1.0f));
assert(isfinite(1.0));
assert(isfinite(1.0L));
#endif // isfinite
```

https://github.com/llvm/llvm-project/pull/97791