The RPC stubs already prefix the command name to error messages.
The daemon doesn't have to do this.  As a (small) benefit this also
makes the daemon slightly smaller.

Code in the daemon such as:

  if (argv[0] == NULL) {
    reply_with_error ("passed an empty list");
    return NULL;
  }

now results in error messages like this:

  ><fs> command ""
  libguestfs: error: command: passed an empty list

(whereas previously you would have seen ..command: command:..)

git grep -l 'strcmp *([^=]*== *0'|xargs \
  perl -pi -e 's/\bstrcmp( *\(.*?\)) *== *0/STREQ$1/g'

git grep -l 'strcasecmp *([^=]*== *0'| xargs \
  perl -pi -e 's/\bstrcasecmp( *\(.*?\)) *== *0/STRCASEEQ$1/'

These commands can be used to list files in the appliance.

Also, ...
* src/generator.ml: Add DeviceList type, and propagate that change
out to all calling/interface code.

Nearly every file-related function in daemons/*.c is affected:
Remove this pair of statements from each affected do_* function:
-  NEED_ROOT (return -1);
-  ABS_PATH (dir, return -1);
and change the type of the corresponding parameter to "const char *".
* src/generator.ml: Emit NEED_ROOT just once, even when there are two or
more Pathname args.

* daemon/debug.c (MAYBE_UNUSED): Define.
(do_debug): Mark parameters as unused only when they really
are unused.  Spotted by Richard Jones.

SCALAR(0xdd8370)
prefer sizeof *VAR sizeof TYPE (no semantic change)

* daemon/debug.c (do_debug): Mark parameters as unused.

Do it by running this command:
[exempted files are matched via .x-sc_TAB_in_indentation]

  git ls-files \
    | pcregrep -vf .x-sc_TAB_in_indentation \
    | xargs pcregrep -l '^ *\t' \
    | xargs perl -MText::Tabs -ni -le \
      '$m=/^( *\t[ \t]*)(.*)/; print $m ? expand($1) . $2 : $_'