For native and cross builds to MinGW (mingw32 or i386-pc-mingw32), Java and libgcj are unnecessarily disabled by the top-level configure - they have been building just fine for quite some time now in mainline. To get libgcj to build, one has to explicitly specify --enable-libgcj to the configure command.
The following simple change fixes this (configure needs to be regenerated): Index: configure.in =================================================================== --- configure.in 2005-02-15 10:36:30.000000000 +0530 +++ configure.in 2005-02-15 10:37:01.000000000 +0530 @@ -588,5 +588,5 @@ case "${target}" in i[[3456789]]86-*-mingw32*) target_configdirs="$target_configdirs target-mingw" - noconfigdirs="$noconfigdirs expect target-libgloss ${libgcj}" + noconfigdirs="$noconfigdirs expect target-libgloss" # Can't build gdb for mingw32 if not native. -- Summary: Java Unnecessarily Disabled for MinGW Product: gcc Version: 4.0.0 Status: UNCONFIRMED Severity: normal Priority: P2 Component: bootstrap AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: rmathew at gcc dot gnu dot org CC: gcc-bugs at gcc dot gnu dot org GCC build triplet: i686-pc-linux-gnu GCC host triplet: i686-pc-linux-gnu GCC target triplet: i386-pc-mingw32 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19970