[BUG] Absolute paths no longer work as input

[alexreinking]

Describe the bug
After the following commit, absolute paths are misinterpreted as unrecognized flags.

16686c1

To Reproduce

~$ git clone https://github.com/hsutter/cppfront
~$ cd cppfront
~/cppfront$ clang++-19 -o cppfront -O2 -std=c++20 source/cppfront.cpp
~/cppfront$ ./cppfront "$PWD/regression-tests/pure2-enum.cpp2"
/home/alex/cppfront/regression-tests/pure2-enum.cpp2 - unknown compiler flag name (try /help)

Additional context
N/A

[sookach]

I'll have a look

[sookach]

Thanks for the bug report! My commit fixes the issue for mac sonoma. Fairly certain it should work on all other platforms, but let me know if you run into any issues.