WIP: Support some sort of inline-only inclusion

We need some way to always inline functions without
even generating a externally callable function.
This is only a proof of concept:
* It does not work across different modules
* This should be done in the frontend

In order to solve this we first have to get get the frontend
inliner working with GCC. This is delayed for now.
Add @attribute("notypeinfo")
Add @attribute("nocode")
Add @attribute("noinit")
Implement pragma(GNU_nomoduleinfo)
Basics
Implement -fno-rtti
Add -fno-utf-foreach
disable AA
Add -microD
microD: no bounds check, no switch error
Add -fstring-switch
Disable module constructors in microD
Add -fmoduleinfo
Do not require _xopEquals in microD

TODO: probably rather set to a special value as NULL is also used
for bitwise copy?
Allow 16bit pointers
Adding libbacktrace to target-libs breaks build

Only require libbacktrace is phobos is actually being built.
Add attribute("cctor") and attribute("cdtor")
Add -ftls-support
Add -fexceptions