Escape multiple arguments in the settings file
Uses responseFile syntax.
The issue arises when GHC is installed on windows into a location that
has a space, for example the user name is 'Fake User'.
The $tooldir will also contain a space, consequentially.
When we resolve the top dir in the string -I$tooldir/mingw/include
,
then words
will turn this single argument into -I/C/Users/Fake
and
User/.../mingw/include
which trips up our flags.
This doesn't break any existing code.
Fixes #24265 (closed)