Re: [C++] include directory configury

[Benjamin Kosnik <bkoz at redhat dot com>]

Hey mark. We do this for the following setup:

x86-x-powerpc-elf
x86-x-arm-elf
x86-native

all with the same prefix. Some of the libstdc++-v3's headers are 
configure-generated, and have to do with configuration particulars 
(atomicity, config.h, etc: you'll find the full list as build_headers in 
src/Makefile.am). Not installing the target-dependent ones in a 
target-dependent place means they all get smashed by the last-installed. 
This is no bueno.

Hopefully this explains the problem of why we mess with this at all.

>   If we put the main include files in /foo/bar/include
>   why not just put (for example) the i686-pc-linux-gnu stuff
>   in /foo/bar/include/i686-pc-linux-gnu?

...that's another way to do it. 

> Anyhow, the point is that the relocatable GCC thing is way cool, and
> now we're back in that state, ugliness aside.

I agree: I'm not trying to make trouble, just trying to get a clean patch 
for everybody's favorite behavior. Having one set of shared c++ includes 
for multiply-targeted c++ compilers is also quite cool.......

> I think if there's something better we can do that's cool, but I guess
> I'm not sure exactly what you're suggesting.  Do you have a patch in
> mind?

I move to have the target-includes in a target-specified directory of the 
main libstdc++-v3 include directory, as you suggested above. Jason has 
also agreed to this in the past, and I believe this will work out ok. 

The compiler and library bits have to be changed in a similar manner.

-benjamin