Package FTBFS on multiple architectures due to apparent bugs in gcc - how to proceed?

I maintain a package (monotone) that fails to build from source on alpha, arm, and ia64 with symptoms that suggest compiler bugs to me. On arm it's clear-cut: cc1plus segfaults. On ia64, there are testsuite failures because exceptions that should have been caught (and are caught on other

gcc-4.2 4.2.4-1 MIGRATED to testing

FYI: The status of the gcc-4.2 source package in Debian's testing distribution has changed. Previous version: 4.2.3-5 Current version: 4.2.4-1 -- This email is automatically generated; [EMAIL PROTECTED] is responsible. See http://people.debian.org/~henning/trille/ for more information.

Bug#484053: g++-4.3: [PR36415] [4.1/4.2 regression, armel] ICE in extract_insn, at recog.c:1990

Package: g++-4.3 Version: 4.3.0-5 Severity: important g++-4.3 fails to build texlive-bin on armel (but not on arm), with the following error: g++ -D_REENTRANT -I../../../../libs/icu-xetex/i18n -I../common -I../../../../libs/icu-xetex/common -D_REENTRANT -DU_I18N_IMPLEMENTATION -g -O2 -c -o