https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69988
--- Comment #3 from John Paul Adrian Glaubitz <glaubitz at physik dot fu-berlin.de> --- Looking at the source code, I found this: ppc_fp_compat= case ${ppc_fp_type} in soft|e500v1|e500v2) if test $glibc_version_major -gt 2 \ || ( test $glibc_version_major -eq 2 \ && test $glibc_version_minor -ge 19 ); then ppc_fp_compat="t-softfp-compat" fi ;; esac ;; esac Which apparently originates here: > https://patchwork.ozlabs.org/patch/405072/ So, it seems that gcc-5 is relying on glibc for providing the softfloat functions and those are particularly not present in static libgcc. The chroot I used for building gcc-5 uses glibc_2.19, so that should be recent enough. Will try disabling the above code and see what happens.