Initial work to enable EventPipe in Linux (#86226)

Initial work to enable EventPipe in Linux (#86226)

* Initial work to enable EventPipe in Linux

* GCC build break fix

* Only enable Unix

* FB

* restricting iOS

* Update src/coreclr/nativeaot/Directory.Build.props

Co-authored-by: Michal Strehovský <MichalStrehovsky@users.noreply.github.com>
* FB

* license header

* Update src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h

Co-authored-by: Elinor Fung <elfung@microsoft.com>
* FB

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Co-authored-by: Michal Strehovský <MichalStrehovsky@users.noreply.github.com>
Co-authored-by: Elinor Fung <elfung@microsoft.com>