* add gotype string to symbol table
* fill in gotype in 6l for known funcs/vars
* print gotype with nm -t
* load symbol and pc/ln tables into memory at magic address 0x99<<32.
* add sys.symdat() to retrieve raw bytes of symbol table
and pc/ln table.
most of this should be considered experimental
and subject to change.
R=r
DELTA=157 (128 added, 0 deleted, 29 changed)
OCL=19746
CL=19750