While evaluating the form starting at line 36, column 0
  of #P"/home/user/quicklisp/local-projects/MBuild/Mezzano/../build-cold-image.lisp":

debugger invoked on a SIMPLE-ERROR in thread
#<THREAD "main thread" RUNNING {1000510083}>:
  Duplicate symbol :PROGN.

Type HELP for debugger help, or (SB-EXT:EXIT) to exit from SBCL.

restarts (invokable by number or by possibly-abbreviated name):
  0: [RETRY   ] Retry EVAL of current toplevel form.
  1: [CONTINUE] Ignore error and continue loading file "/home/user/quicklisp/local-projects/MBuild/Mezzano/../build-cold-image.lisp".
  2: [ABORT   ] Abort loading file "/home/user/quicklisp/local-projects/MBuild/Mezzano/../build-cold-image.lisp".
  3:            Ignore runtime option --load "../build-cold-image.lisp".
  4:            Skip rest of --eval and --load options.
  5:            Skip to toplevel READ/EVAL/PRINT loop.
  6: [EXIT    ] Exit SBCL (calling #'EXIT, killing the process).

(MEZZANO.LAP::PERFORM-ASSEMBLY-PASS1 #<HASH-TABLE :TEST EQL :COUNT 105 {1002611693}> (MEZZANO.COMPILER.BACKEND.ARM64::ENTRY-POINT (:DEBUG NIL) (:GC :NO-FRAME :INCOMING-ARGUMENTS :RCX :LAYOUT #*) (MEZZANO.LAP.ARM64:STP :X29 :X30 (:PRE :SP -16)) (:GC :NO-FRAME :INCOMING-ARGUMENTS :RCX :LAYOUT #*00) (MEZZANO.LAP.ARM64:ADD :X29 :SP :XZR) (:GC :FRAME :INCOMING-ARGUMENTS :RCX) (MEZZANO.LAP.ARM64:SUB :SP :SP 16) (MEZZANO.LAP.ARM64:STR :X26 (:X29 -8)) (MEZZANO.LAP.ARM64:STR :X26 (:X29 -16)) (:GC :FRAME :LAYOUT #*11 :INCOMING-ARGUMENTS :RCX) (:DEBUG NIL) ...) 16)
   source: (ERROR "Duplicate symbol ~S." I)
0]