[Bug libstdc++/120160] Implicitly import std if standard library header is included

[de34 at live dot cn via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120160

Jiang An <de34 at live dot cn> changed:

           What    |Removed                     |Added
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                 CC|                            |de34 at live dot cn

--- Comment #1 from Jiang An <de34 at live dot cn> ---
`import std;` in every header looks too heavy to me. IMO it's undesired to
import std::cin and its friends from <vector>.