fix(examples/gccflags): Bytes/String mismatch when parsing GCC output on Python3

[mihaescuvlad]

Context

When running the matrixmultiply.cpp or raytracer.cpp on Python 3.12-3.13 (tested on 3.12.3, 3.13.3 and 3.13.7), some parts of the GCC flags extraction and compilation parsing fail because of type differences between bytes and string types.

These differences caused TypeError: cannot use a string pattern on a bytes-like object to get thrown.

Changes

• Decoded subprocess output to string before regex
• Decoded all GCC stderr messages before logging
• Fixed parsing for --version, --help=params, and --help=optimizers

Testing

Reran the examples like normal using new virtual environments running on Python 3.12.3, 3.13.3 and 3.13.7

python gccflags.py apps/matrixmultiply.cpp
python gccflags.py apps/raytracer.cpp