This fixes backend/peephole.c.

Assembler/linker never supported this anyway.

It has been empty for nearly all systems. People who used to put stuff
in config.h can still create a config.h on their own and inject
-include (gcc) or /FI (msvc) into their CPPFLAGS.

An ia32 Load always loads into a GP register.

There is not (middleend) Start node in a graph at this point.

Just state the copyright and the project the files belong to. You can
then find the COPYING file for the whole project.

cleanup: Remove pointless assert(is_${NODE}(x)) just before get_${NODE}_${FOO}(x), which do the same assert.

The middleend should optimize all these cases, it does so for 99% of
them already. There are just some cases where ands get transformed into
conversions which the middleend doesn't catch yet.

The opcode list was a member of irprog before which wasn't really
handled consistently. Also make sure opcodes are properly freed at
ir_finish().