Update asan environment to better show errors

Author: rhpvorderman

tox.ini

@@ -23,8 +23,10 @@ commands =
 [testenv:asan]
 setenv=
     PYTHONDEVMODE=1
+    PYTHONUNBUFFERED=1
     PYTHONMALLOC=malloc
-    CFLAGS=-lasan -fsanitize=address -fno-omit-frame-pointer
+    CFLAGS=-lasan -fsanitize=address -fno-omit-frame-pointer -Og -g
+    ASAN_OPTIONS=log_path=asan_errors
 allowlist_externals=bash
 commands=
     bash -c 'export LD_PRELOAD=$(gcc -print-file-name=libasan.so) && printenv LD_PRELOAD && python -c "from zlib_ng import zlib_ng" && pytest tests'