Change activation of debug mode

Author: Joao-Dionisio

docs/build.rst

@@ -160,7 +160,8 @@ To use debug information in PySCIPOpt you need to build it with the following co
 
 .. code-block::
 
-  python -m pip install --install-option="--debug" .
+  export PYSCIPOPT_DEBUG=True
+  python -m pip install .
 
 .. note:: Be aware that you will need the debug library of the SCIP Optimization Suite for this to work
   (cmake .. -DCMAKE_BUILD_TYPE=Debug).

setup.py

@@ -62,9 +62,8 @@
     extra_link_args.append(f"-Wl,-rpath,{libdir}")
 
 # enable debug mode if requested
-if "--debug" in sys.argv:
+if os.environ.get("PYSCIPOPT_DEBUG")==True:
     extra_compile_args.append("-UNDEBUG")
-    sys.argv.remove("--debug")
 
 use_cython = True