zld: fix incorrectly worked out section size

Also, add a solution to a degenerate case where on x86_64 a relocation
refers to a cell in a section via section start address even though
a symbol exists. In such case, make the section spawned symbol an alias
of the actual symbol.
e17f12dd64Jakub Konka committed on 7/15/2021, 4:49:47 PMparentde30a70
3 files changedLine totals unavailable