build win/mac: do not pass custom args to pyinstaller; use envvars

custom args no longer work with pyinstaller 5.0 (see https://github.com/pyinstaller/pyinstaller/issues/6762 )

```
option(s) not allowed:
  ...
makespec options not valid when a .spec file is given
```

contrib/build-wine/deterministic.spec

@@ -2,12 +2,10 @@
 
 from PyInstaller.utils.hooks import collect_data_files, collect_submodules, collect_dynamic_libs
 
-import sys
-for i, x in enumerate(sys.argv):
-    if x == '--name':
-        cmdline_name = sys.argv[i+1]
-        break
-else:
+import sys, os
+
+cmdline_name = os.environ.get("ELECTRUM_CMDLINE_NAME")
+if not cmdline_name:
     raise Exception('no name')
 
 home = 'C:\\electrum\\'