I'm trying to compile g++ 4.7.1 from source on Ubuntu 12.04 32 bits. For the moment I've exactly done that : https://askubuntu.com/questions/168947/how-to-upgrade-g-to-4-7-1 Except just before the compilation of g++ 4.7.1 it asks me to "unset LIBRARY_PATH" (so I've done that). So the compilation starts, and after a while I have the following error message :

In file included from ../.././gcc/c-lang.c:24:0:
../.././gcc/system.h:499:20: erreur: conflicting types for ‘strsignal’
/usr/include/string.h:566:14: note: previous declaration of ‘strsignal’ was here
In file included from ./tm.h:19:0,
                 from ../.././gcc/c-lang.c:26:
./options.h:3738:2: erreur: #error too many masks for ix86_isa_flags
In file included from ../.././gcc/input.h:25:0,
                 from ../.././gcc/tree.h:27,
                 from ../.././gcc/c-lang.c:27:
../.././gcc/../libcpp/include/line-map.h:208:38: erreur: ‘CHAR_BIT’ undeclared here (not in a function)
../.././gcc/../libcpp/include/line-map.h:208:3: erreur: bit-field ‘reason’ width not an integer constant
../.././gcc/../libcpp/include/line-map.h:208:3: attention : ‘reason’ is narrower than values of its type [enabled by default]
In file included from ../.././gcc/tree.h:32:0,
                 from ../.././gcc/c-lang.c:27:
../.././gcc/hwint.h:17:39: erreur: division par zéro dans #if
../.././gcc/hwint.h:17:39: erreur: division par zéro dans #if
../.././gcc/hwint.h:17:39: erreur: division par zéro dans #if
../.././gcc/hwint.h:17:39: erreur: division par zéro dans #if
../.././gcc/hwint.h:17:39: erreur: division par zéro dans #if
../.././gcc/hwint.h:17:39: erreur: division par zéro dans #if
../.././gcc/hwint.h:17:39: erreur: division par zéro dans #if
../.././gcc/hwint.h:17:39: erreur: division par zéro dans #if
../.././gcc/hwint.h:17:39: erreur: division par zéro dans #if
../.././gcc/hwint.h:17:39: erreur: division par zéro dans #if
.
c++ compilation g++ ubuntu-12.04
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