Don't worry anymore. I decided to upgrade to edgy and to trash firefox pre-3.0 alpha1 build process. I will use official nightlies instead of homemade ones.
Thanks anyway for having tried to find what was bugging. -- Build process of firefox trunk is broken with both gcc 4.1.1 and gcc 4.0 ! https://launchpad.net/bugs/61104 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
