Fix bug where pcsp and nameOff would be 0 for the first entries in th…

…e funcnametab and pctab (which runtime treats as missing/empty)

ld.go

@@ -75,6 +75,13 @@ var (
 // initialize Linker
 func initLinker() *Linker {
 	linker := &Linker{
+		// Pad these tabs out so offsets don't start at 0, which is often used in runtime as a special value for "missing"
+		// e.g. runtime/traceback.go and runtime/symtab.go both contain checks like:
+		// if f.pcsp == 0 ...
+		// and
+		// if f.nameoff == 0
+		funcnametab:  make([]byte, PtrSize),
+		pctab:        make([]byte, PtrSize),
 		symMap:       make(map[string]*obj.Sym),
 		objsymbolMap: make(map[string]*obj.ObjSymbol),
 		namemap:      make(map[string]int),