CI fixes: patchelf dev dep for auditwheel, absolute paths in setup.py

- Linux runner lacks patchelf; add the patchelf PyPI package (linux
  only) to dev deps so uv run puts it on PATH for auditwheel repair.
- setup.py anchored all libaegis paths to __file__: newer setuptools
  invoke the compiler from a temp build dir, breaking CWD-relative
  -Ilibaegis/src/include on Windows (C1083 aegis.h not found).

pyproject.toml

@@ -26,6 +26,7 @@ Repository = "https://github.com/LeoVasanko/aegis-python"
 [dependency-groups]
 dev = [
     "auditwheel>=6.8.2",
+    "patchelf>=0.17; sys_platform == 'linux'",
     "pytest>=9.1.1",
     "ruff>=0.16.10",
     "setuptools>=84.0.0",

setup.py

@@ -7,12 +7,14 @@ from pathlib import Path
 from cffi import FFI
 from setuptools import setup
 
-libaegis_static = Path("libaegis/zig-out/lib") / (
+ROOT = Path(__file__).parent.resolve()
+
+libaegis_static = ROOT / "libaegis/zig-out/lib" / (
     "aegis.lib" if sys.platform == "win32" else "libaegis.a"
 )
 
 ffibuilder = FFI()
-ffibuilder.cdef((Path(__file__).parent / "src/aeg/aegis_cdef.h").read_text())
+ffibuilder.cdef((ROOT / "src/aeg/aegis_cdef.h").read_text())
 
 # Free-threaded Python does not support Limited API (abi3)
 is_free_threaded = sysconfig.get_config_var("Py_GIL_DISABLED")
@@ -28,8 +30,8 @@ ffibuilder.set_source(
     #include "aegis256x2.h"
     #include "aegis256x4.h"
     """,
-    include_dirs=["libaegis/src/include"],
-    extra_objects=[str(libaegis_static.resolve())],
+    include_dirs=[str(ROOT / "libaegis/src/include")],
+    extra_objects=[str(libaegis_static)],
     py_limited_api=not is_free_threaded,
 )