use feature ":5.14";
use warnings FATAL => qw(all);
use strict;

my ($c, $s) = (0, '');
for(split /\n/, << 'END') 
LABEL#00001
         
		 MVC   SYMBOL+2(4),X.PDES_KEY+2                                         
         MVC   SYMB_ART,=C'XSEQ'              //line comments                                  
                                                                                
         F$SFH SELECT,LISTING,                                         *        
               DESKART=SYMB_ART,                                       *        
               DESKWERT=SYMBOL,                                        *        
               MARKTCODE=L#MACF                                                 
         BNE   F03#000                     //line comments
END

 {if (length > 71 and substr($_, 71, 1) eq '*') # Detect continuation
   {s/\A\s*// if $c == 1;                       # Strip leading space in continuation  
    s/\s*\*\s*\Z//;                             # Strip trailing space
    ($s, $c) = (($c ? $s : '').$_, 1);          # Concatenate or restart depending on continuation state
   }
  else
   {s/\A\s*// if $c == 1;                       # Strip leading spaces in continuation
    say "$s$_";                                 # Write completed statement
    ($s, $c) = ('', 0);                         # Restart
   }
 }

##</code><code>##

LABEL#00001
         
		 MVC   SYMBOL+2(4),X.PDES_KEY+2                                         
         MVC   SYMB_ART,=C'XSEQ'              //line comments                                  
                                                                                
         F$SFH SELECT,LISTING,DESKART=SYMB_ART,DESKWERT=SYMBOL,MARKTCODE=L#MACF                                                 
         BNE   F03#000                     //line comments