sys/_types.h: Actually unbreak gcc build

[des]

Summary

Fixes: 19728f31ae42 ("sys/_types.h: Unbreak gcc build")

[des]

So I checked and the preprocessor _does_ do short-circuit evaluation of boolean expressions, so this shouldn't be necessary, yet gcc complains:

sys/sys/_types.h:164:46: error: missing binary operator before token "("
  164 | #if !defined(__has_feature) || !__has_feature(capabilities)
      |                                              ^

[markj]

sys/sys/_types.h

167

Why not just write

#ifdef __has_feature
#if !__has_feature(capabilities)

?

With that change, the gcc13 build completes successfully for me.

[des]

sys/sys/_types.h

167

Because that inverts the logic. We want these lines included in all cases /except/ when the compiler has the capabilities feature.