convert note_data to a value from a pointer (#16661)

compiler/src/dmd/backend/elfobj.d

@@ -205,7 +205,7 @@ struct ElfObj
 
  OutBuffer shndx_data; // Extended section header indices
 
- OutBuffer* note_data; // Notes data (note currently used)
+ OutBuffer note_data;  // Notes data (note currently used)
 
  IDXSEC secidx_note; // Final table index for note data
 
@@ -607,7 +607,7 @@ Obj ElfObj_init(OutBuffer *objbuf, const(char)* filename, const(char)* csegname)
  cseg = CODE;
  elfobj.fobjbuf = objbuf;
 
- elfobj.note_data = null;
+ elfobj.note_data.reset();
  elfobj.secidx_note = 0;
  elfobj.comment_data = null;
  elfobj.seg_tlsseg = UNKNOWN;
@@ -722,8 +722,7 @@ Obj ElfObj_init(OutBuffer *objbuf, const(char)* filename, const(char)* csegname)
  elfobj.shndx_data.reset();
  elfobj.shndx_data.reserve(50 * (Elf64_Word).sizeof);
 
- if (elfobj.note_data)
- elfobj.note_data.reset();
+ elfobj.note_data.reset();
 
  if (elfobj.comment_data)
  elfobj.comment_data.reset();
@@ -1058,7 +1057,7 @@ void ElfObj_term(const(char)[] objfilename)
 
  /* Next output any notes or comments
  */
- if (elfobj.note_data)
+ if (elfobj.note_data.length())
  {
  sechdr = &elfobj.SecHdrTab[elfobj.secidx_note]; // Notes
  sechdr.sh_size = cast(uint)elfobj.note_data.length();