[Mingw-msys] [Patch] translate response file names

[Charles W. <cwi...@us...>]

Many of the GNU toolchain executables (gcc, binutils) accept "response
file" arguments:

	ar cru lib1.a @list-of-objects.txt

where the specified file is parsed, one line at a time, to generate
additional command line arguments. This way, the tools can work around
limitations in command line length.  However, the following currently
doesn't work, if 'ar' is the MinGW version, and the command is executed
in an MSYS shell:

$ /mingw/bin/ar cru lib1.a @/home/me/fnlist.txt
C:\MinGW\bin\ar.exe: @/home/me/fnlist.txt: No such file or directory

Because the native ar.exe has no idea where "/home/me/fnlist.txt" is.
The attached patch teaches msys to translate arguments that start with
'@' from unix to w32 when launching native applications (just like it
currently translates -L/a/unix/path)

2010.09.04  Charles Wilson  <...>

       * path.cc (msys_p2w): Support conversion of @file
       arguments.

OK to commit?

--
Chuck