-fvia-c doesn't work

[Sven Panne]

Simon Marlow wrote:
>>[...] OK, after a couple more strange experiences, whereby -fvia-c sometimes
>>worked and sometimes did not, depending on what directory I was in,
>>I finally determined that the failure happened only when I had a file
>>called "stdint.h" in the current directory.
>>
>>So apparently, since a straight call of gcc does not display the same
>>problem, the search path given to gcc by ghc somehow has . before
>>the standard location of /usr/include?
> 
> 
> Thanks for tracking this down.  For a workaround, you can say 
> 
>    ghc -I- ...
> 
> this causes ghc to pass '-I-' to gcc, which causes gcc to interpret all
> the include paths as applying only to includes of the form #include
> "...".  Includes of the form #include <...> will be searched for in the
> system directories only.  Put the -I- after any other -I options on the
> ghc command line.
> 
> I've made this change in GHC, but I probably won't merge it into 6.2.2
> because it's only of those changes that could easily cause something
> else to break, so we need plenty of testing.

FYI: This change breaks things quite badly, e.g. a simple

    #include <GL/glut.h>

fails for me now, because /usr/include/GL/glut.h contains

    #include "freeglut_std.h"

But with -I-, /usr/include/GL/freeglut_std.h will not be found. A quick
grep through the system header on my SuSE 9.1 shows that there are dozens
of similar #includes. If I can't find a fix for this, I'll revert the change.

Hmmm, why do we use a "-I ." in the first place...?

Cheers,
    S.