adds support for usage of pip option config settings

pyproject.toml

@@ -5,4 +5,5 @@ requires = [
     "cmake",
     "ninja; platform_system!='Windows'"
 ]
-build-backend = "setuptools.build_meta"
\ No newline at end of file
+build-backend = "setup_builder"
+backend-path = ["utilities"]
\ No newline at end of file

setup.py

-import inspect
 import sys
 from pathlib import Path
 
 import skbuild
-import setuptools
 
 """
 Install python wrapper of virtual fluids
 install via python:
     python setup.py install build_ext
     set CMAKE Flags via -DBUILD_VF_GPU:BOOL=1
+    CMAKE flags have to be separated by -- 
+    example: python setup.py install build_ext -- VBUILD_VF_CPU:BOOL=ON
 or install via pip:
     pip install -e .
     set CMAKE Flags via --config-settings -DBUILD_VF_GPU=1
@@ -29,6 +29,9 @@ init_file.write_text(init_py)
 name_of_build_dir = "build"
 
 build_dir = (top_dir/name_of_build_dir).mkdir(exist_ok=True)
+extra_args = []
+if("cmake_args" in locals()):
+    extra_args.extend([f"{k}={v}" for k,v in locals()["cmake_args"].items()])
 
 cmake_args = [
         f"-DPython3_ROOT_DIR={Path(sys.prefix)}",
@@ -37,7 +40,7 @@ cmake_args = [
         "-DBUILD_VF_DOUBLE_ACCURACY=OFF",
         "-DBUILD_VF_UNIT_TESTS:BOOL=OFF",
         "-DBUILD_WARNINGS_AS_ERRORS=OFF",
-    ]
+    ] + extra_args
 
 skbuild.setup(
     name="pyfluids",