python-bsddb3: don't set runtime_library_dirs

Not supported on Windows

In our stdlib distutils it will end up using rpath, which clang errors out on,
and in upstream distutils there is a PR pending making it a proper error:
https://github.com/pypa/distutils/pull/150

mingw-w64-python-bsddb3/unsupported-runtime-dirs.patch

@@ -0,0 +1,10 @@
+--- bsddb3-6.2.9/setup3.py.orig	2022-06-12 09:37:28.978102500 +0200
++++ bsddb3-6.2.9/setup3.py	2022-06-12 10:00:04.408752300 +0200
+@@ -539,7 +539,6 @@
+                                depends = ['Modules/bsddb.h'],
+                                include_dirs = [ incdir ],
+                                library_dirs = [ libdir ],
+-                               runtime_library_dirs = [ libdir ],
+                                libraries = libname,
+                                extra_link_args = lflags_arg,
+                                )],