[libcxx] moves `std::invoke` into `__functional_base`
Including `<concepts>` in other standard library headers (such as
`<iterator>`) creates circular dependencies due to `<functional>`.
Since `<concepts>` only needs `std::invoke` from `<functional>`, the
easiest, fastest, and cleanest way to eliminate the circular dep is to
move `std::invoke` into `__functional_base`.
This has the added advantage of `<concepts>` not transitively importing
`<functional>`.
Differential Revision: https://reviews.llvm.org/D99041
GitOrigin-RevId: c25c22d5f9b7e56c0c350982b5ec41095c5a0a05
diff --git a/include/concepts b/include/concepts
index 0a3e927..070e1df 100644
--- a/include/concepts
+++ b/include/concepts
@@ -135,7 +135,7 @@
*/
#include <__config>
-#include <functional>
+#include <__functional_base>
#include <type_traits>
#include <utility>
#include <version>