fix: restore iota blocks, asm --format flag and prose after the syntax pass

asm/elf.go

@@ -17,7 +17,6 @@ import (
 // and external ones against undefined globals.  The output links with the
 // system toolchain (cc/ld) the way a hand-assembled .o would.
 
-// ELF constants (ELF64, little-endian, System V).
 const (
 	elfClass64 = 2
 	elfDataLSB = 1
@@ -36,17 +35,14 @@ const (
 	shfAlloc     = 2
 	shfExecInstr = 4
 
-	stbLocal  = 0
 	stbGlobal = 1
 
-	sttNotype   = 0
 	sttObject   = 1
 	sttFunc     = 2
 	sttSection  = 3
 	stInfoShift = 4
 
 	rX8664PC32 = 2
-	rX8664_64  = 1 // R_X86_64_64 (absolute 64-bit)
 )
 
 // elfSym is one symbol-table entry in construction.