Combined tree builds for mingw32

[Paolo Carlini]

Daniel Jacobowitz wrote:

>The failing command is trying to compile the PCH.  This means that
>we're including a large number of libstdc++ headers in a row.  One of
>the first ones pulls in c++config.h, which has #undef max; but so far,
>nothing has included <windows.h>.  Later, something includes
>gthr-default.h; on this platform that pulls in <windows.h>, which
>eventually #define's min.  Then later we get <limits>, which now sees
>the definition.
>  
>
I see, but I still don't get why this is worse than time ago, when the 
undefs where placed in the middle of stl_algobase.h and nowhere else. Do 
you?

>Hmm, there are three <ctype.h>'s in the src repository:
>
>/space/fsf/commit/src/newlib/libc/include/ctype.h
>/space/fsf/commit/src/winsup/cygwin/include/ctype.h
>/space/fsf/commit/src/winsup/mingw/include/ctype.h
>
>That third one does not define _U.  It uses _UPPER instead.  Does this
>mean --with-newlib does not work for mingw32?
>
No idea, absolutely, I don't know the source directory. But, again, I 
don't see, in general, why things are worse than some time ago. In the 
libstdc++-v3 directory nothing changed about ctype_base.h lately, it 
doesn't include anything, and is only included after <cctype>.

Paolo.