Use Clang and make build parameters identical to PCSX2

[charlesthobe]

except USE_SYSTEM_ZSTD=OFF

This provides a performance boost since CMAKE_BUILD_TYPE=RelWithDebInfo prevented inlining which is an optimization technique, also because clang produces slightly faster binaries according to PCSX2 devs.

[flathubbot]

Started test build 45156

[flathubbot]

Build 45156 successful To test this build, install it from the testing repository:

flatpak install --user https://dl.flathub.org/build-repo/27775/net.pcsx2.PCSX2.flatpakref

[flathubbot]

Started test build 45159

[flathubbot]

Build 45159 successful To test this build, install it from the testing repository:

flatpak install --user https://dl.flathub.org/build-repo/27778/net.pcsx2.PCSX2.flatpakref

[j8r]

RelWithDebInfo was used to pass the flatpak linter. Not needes anymore thanks to https://github.com/flathub/flatpak-builder-lint/issues/41

[j8r]

Thanks! It will be interesting to know if there is any actual performance difference between the LLVM and the GCC build.

[j8r]

Thanks! It will be interesting to know if there is any actual performance difference between the LLVM and the GCC build.

[charlesthobe]

You're welcome, it should be minimal, but enough to make some members of the pcsx2 team care.

[charlesthobe]

RelWithDebInfo was used to pass the flatpak linter. Not needes anymore thanks to flathub/flatpak-builder-lint#41

if "-g" compiler flag is set then there's another problem with inlining optimization that needs solving, will look into it.

[charlesthobe]

Nevermind, -g doesn't stop inlining from taking place.