When GHC links binaries on windows, we pass a -L and -l flag
to gcc for each dependency in the transitive dependency
closure. As this will usually overflow the command argument
limit on windows, we use response files to pass all arguments
to gcc. gcc however internally passes only the -l flags via
a response file to the collect2 command, but puts the -L flags
on the command line. As such if we pass enough -L flags to
gcc--even via a response file--we will eventually overflow the
command line argument length limit due to gcc passing them
to collect2 without resorting to a response file.
To prevent this from happening we move all lirbaries into a
shared temporary folder, and only need to pass a single -L
flag to gcc. Ideally however this was fixed in gcc.