GCC automatically resolves weakly defined empty symbols to null if not overridden, but Clang doesn't resolve it this way. This causes undefined reference errors during linking.

To address this, define empty no-op serialEvent() functions that can be overridden later since its weakly defined, ensuring compatibility with Clang and fixing the build issue.
ref: avr-llvm/clang#9

Signed-off-by: Dakkshesh <dakkshesh5@gmail.com>

Signed-off-by: Dakkshesh <dakkshesh5@gmail.com>

Signed-off-by: Dakkshesh <dakkshesh5@gmail.com>

Signed-off-by: Dakkshesh <dakkshesh5@gmail.com>

- Causes some weird issues, will investigate it later.

Signed-off-by: Dakkshesh <dakkshesh5@gmail.com>

Signed-off-by: Dakkshesh <dakkshesh5@gmail.com>

As reported in [1] and verified in [2] adding -mno-relax seems to fix the LED blinking issues without needing to disable LTO for the affected files. Use this as a temporary workaround until the issue is fixed.

Remove the usage of clang-wrapper for c and cpp cmds since its not required anymore.

[1]: llvm/llvm-project#133579
[2]: llvm/llvm-project#127651 (comment)

Signed-off-by: Dakkshesh <dakkshesh5@gmail.com>

Signed-off-by: Dakkshesh <dakkshesh5@gmail.com>