It's possible you'll need to regenerate the libjava/configure script and the libjava/tools/Makefile.in template, because since libjava was removed from GCC the rest of the source tree was updated to use a newer automake and autoconf: https://gcc.gnu.org/g:22e052725189a472e4e86ebb6595278a49f4bcdd Update GCC to autoconf 2.69, automake 1.15.1 (PR bootstrap/82856). Maybe it doesn't matter, if the libjava configure is self-contained. But it's something to be aware of.