See testcase (from grischka). If the asm has no .globl,
but there's a (non-static) C definition the symbol should
be exported, even if the first reference comes from asm.
This makes the asm symbols use the same members as the C symbols
for global decls, e.g. using the ELF symbol to hold offset and
section. That allows us to use only one symbol table for C and
asm symbols and to get rid of hacks to synch between them.
We still need some special handling for symbols that come purely
from asm sources.
See testcase. The C and asm symtab are still separate,
but integrated tighter: the asm labels are only synched at file
end, not after each asm snippet (this fixes references from one
to another asm block), the C and asm syms are synched both ways,
so defining things in asm and refering from C, or the other way
around works. In effect this model reflects what happens with
GCC better.
For this the asm labels aren't using the C label namespace anymore,
but their own, which increases the size of each TokenSym by a pointer.
