regen everything for GCC 10.4.0.

mknative-gcc for GCC 10 and almost all platforms. one of the
myriad of arm platforms, and the powerpc* platforms are not
yet done.

mknative-gcc for gcc 9.3.0 and arm, earmv[467]*, i386, mipseb, mips64*,
and powerpc64.

regen arm ports for config.gcc fix.