[Bug bootstrap/91602] GCC fails to build for riscv in a combined tree due to misconfigured leb128 support

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91602

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Seems like uleb128 is not supported at all in riscv.  This should be fixed on
the gas side.  No other target has issues with uleb128.