bug#25882: gcc-wrapper doesn't handle response files

[Federico Beffa <beffa@ieee.org>]

ludo@gnu.org (Ludovic Courtès) writes:

> On closer inspection, it’s an easy change to make.
>
> Could you test the attached patch with GHC?

Thanks for the patch.  I've tested it with GHC 8.0.2 and seems to work
for it.  However, this is an excerpt of the description of the use of
response files from the GCC manual:

--8<---------------cut here---------------start------------->8---
'@FILE'
     Read command-line options from FILE.  The options read are inserted
     in place of the original @FILE option.  If FILE does not exist, or
     cannot be read, then the option will be treated literally, and not
     removed.

     Options in FILE are separated by whitespace.  A whitespace
     character may be included in an option by surrounding the entire
     option in either single or double quotes.  Any character (including
     a backslash) may be included by prefixing the character to be
     included with a backslash.  The FILE may itself contain additional
     @FILE options; any such options will be processed recursively.
--8<---------------cut here---------------end--------------->8---

The patch doesn't seems to handle several things, such as missing files,
recursion and use of quotes.  I would suggest to try to match the
expected behavior in its entirety (or at least a larger part thereof).

Fede