[jdk18] RFR: 8279370: jdk.jpackage/share/native/applauncher/JvmLauncher.cpp fails to build with GCC 6.3.0

[Alexander Matveev]

On Mon, 3 Jan 2022 08:10:27 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Seems like a missing include. C++ docs say `offsetof` is from `<cstddef>`, adding that include explicitly fixes the build. Seems to only happen with older GCCs, but it seems to be a happy accident it works on newer ones, probably through the transitive include somewhere.
> 
> Additional testing:
>  - [x] Linux x86_64 fastdebug `tools/jpackage` tests
>  - [x]  Linux x86_64 release `tools/jpackage` tests

Marked as reviewed by almatvee (Reviewer).

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PR: https://git.openjdk.java.net/jdk18/pull/74