Fix some multi-file corner cases with asm

Fix some multi-file corner cases with asm

for this we have to create also asm symbols as VT_STATIC initially
except if there's an indication that it should be global (.globl
or undefined at end of unit).  For this to work we need to
be able to globalize symbols after they were local and enter them
into the ELF hash tables, and also adjust the symbols that were
potentially already used in relocs when they were still local.

The easiest is to do a proper symbol resolution step also in multi-file
mode, for regular symbols (the non-dynamic ones, i.e. not from shared
libs).