Added a=b=c struct copy bug
Fixed decl-without-statement ICE
Merge branch 'master' into feature/bitfields

Brought in mixed code + decls fix.
Store first_off for next bitfield (wasn't missed)
Fixed sizeof(bitfield) detection
Bitfield tests - zero struct first and split out & and sizeof
Factored bitfield prevention for sizeof+addressof
Maximum size check on bitfields