I get this when I'm building a cross compiler for mingw-w64 with gcc-trunk now: libbacktrace/unknown.c:1:0: error: -fPIC ignored for target (all code is position independent) [-Werror] using --disable-werror does not fix it. The workaround I found was to remove -fPIC from PIC_FLAG in $builddir/x86_64-w64-mingw32/libbacktrace/Makefile.
