Add support for symbol stripping

[am11]

Usage:

dotnet publish -c Release -p:PublishAot=true -p:StripSymbols=true --use-current-runtime

Also added a fallback for compiler introspection (clang or gcc).

Fixes #69847

[ghost]

I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label.

[hez2010]

How about making StripSymbols default to true?

[am11]

How about making StripSymbols default to true?

Per @MichalStrehovsky's findings #69847 (comment), other (comparable) toolchains produce unstripped binaries by default.

[jkotas]

Could you please also update https://github.com/dotnet/runtime/blob/main/src/coreclr/nativeaot/docs/optimizing.md#special-considerations-for-linuxmacos ?

[jkotas]

Thank you!

[jkotas]

@MichalStrehovsky Could you please review this as well?

[Suchiman]

How is this different from setting <DebugSymbols>false, which respectively sets <NativeDebugSymbols>false which enables stripping by appending -Wl,--strip-debug to the linker args?

[MichalStrehovsky]

How is this different from setting <DebugSymbols>false, which respectively sets <NativeDebugSymbols>false which enables stripping by appending -Wl,--strip-debug to the linker args?

<DebugSymbols>false</DebugSymbols> will throw away all debugging information on all platforms.

The new <StripSymbols> option places debugging information on non-Windows systems into a separate file, similar to Windows PDB.

[MichalStrehovsky]

Thank you!

[am11]

StripSymbols strips away all the unneeded symbols from binary and place them into a separate file, not just the debug symbols.

Original size of Hello World executable on linux: 18 MB
With -p:NativeDebugSymbols=false: 11 MB
With -p:StripSymbols=true: 5.7 MB

[MichalStrehovsky]

The NativeAOT leg failed because there was a Helix delay of 1 hour and 40 minutes for System.IO.FileSystem.Tests:

"Queued":"2022-06-06T04:42:54.942+00:00",
"Started":"2022-06-06T06:23:06.736+00:00",
"Finished":"2022-06-06T06:23:07.158+00:00",
"Delay":"01:40:11.7940000",
"Duration":"00:00:00.4220000"

We'll have to see if this is a pattern.

Cc @LakshanF just FYI