Hi!
On Fri, 28 Sep 2012 09:56:41 +0200, Samuel Thibault <samuel.thiba...@gnu.org>
wrote:
> Thomas Schwinge, le Thu 27 Sep 2012 09:15:23 +0200, a écrit :
> > On Wed, 26 Sep 2012 16:02:29 +0200, Svante Signell
> > <svante.sign...@telia.com> wrote:
> > > gdb does not build from source any longer since gdb-multiarch packages
> > > was enabled in 7.4.1-1. The build problems are due to two reasons:
> >
> > I also once had a look and came to the same conclusion.
> >
> > > First the reserved keyword MACH is defined in include/objcode/h8300.h
> > > causing problems since gcc defines it for GNU/Hurd.
> >
> > Correct. And I wonder if that isn't a name-space violation? This is
> > what I meant to look up when working on this two months ago, but then it
> > seems I again got distracted by other issues. Roland, do you have any
> > comments regarding that?
> >
> > [GCC]/gcc/config/gnu.h:
> > [...]
> > #undef GNU_USER_TARGET_OS_CPP_BUILTINS
> > #define GNU_USER_TARGET_OS_CPP_BUILTINS() \
> > do { \
> > builtin_define ("__gnu_hurd__"); \
> > builtin_define ("__GNU__"); \
> > builtin_define_std ("unix"); \
> > builtin_define_std ("MACH"); \
> > builtin_assert ("system=gnu"); \
> > builtin_assert ("system=mach"); \
> > builtin_assert ("system=unix"); \
> > builtin_assert ("system=posix"); \
> > } while (0)
> >
> > $ gcc -dM -E -x c - < /dev/null | grep -i mach
> > #define __MACH 1
> > #define __MACH__ 1
> > #define MACH 1
>
> On Linux i386, both "linux" and "i386" macros are defined, which poses
> its own problems too.
(Let's pause for a moment in remembrance of the »glibc vs. i686 defined«
issue that would nearly have seen its 10th anniversary these days.)
> I'd indeed tend to say that defining a non-underscored macro is only a
> way for troubles.
>
> > Could we/should we remove the latter one? Though, I have no idea how
> > much user code is relying on MACH being #defined. I had a colleague
> > check, and Apple/Darwin systems do *only* #define __MACH__ (as well as
> > __APPLE__).
Here is the straightforward patch. With it, only the __MACH__ built-in
preprocessor macro remains, and we get:
[...]
Fixing headers into /home/thomas/tmp/gnu-0/obj/gcc/gcc/include-fixed for
i686-pc-gnu target
-Forbidden identifiers: MACH i386 unix
+Forbidden identifiers: i386 unix
[...]
These two are to remain.
diff --git gcc/config/gnu.h gcc/config/gnu.h
index dddbcbf..4d9449e 100644
--- gcc/config/gnu.h
+++ gcc/config/gnu.h
@@ -34,7 +34,7 @@ along with GCC. If not, see <http://www.gnu.org/licenses/>.
builtin_define ("__gnu_hurd__"); \
builtin_define ("__GNU__"); \
builtin_define_std ("unix"); \
- builtin_define_std ("MACH"); \
+ builtin_define ("__MACH__"); \
builtin_assert ("system=gnu"); \
builtin_assert ("system=mach"); \
builtin_assert ("system=unix"); \
Samuel, is there any way you can unpack all Debian source packages on a
Debian machine, and run a recursive grep command (I can work out a
suitable regex) to see where removing the MACH or __MACH built-in
preprocessor macros might cause trouble?
Grüße,
Thomas
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