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
Add -fclasses

microD will support classes, but this will be useful for -fstandalone: A
mode which will not require any external functions. (gcc.attributes and
gcc.builtins headers may still be required at compile time)
Revert "Fix Bug 139 - writes all-zero initialisers in the rodata section"

This reverts commit 0fcf8babc0d0af85a9a04aaa23b5856237fbdb9f.
FIXME: Always allow features in CTFE

Also have to do this in declarations.c, mtype.c