Signed-off-by: Petr Mladek <pmladek@suse.cz>

Provide HeadlessSalSystem::ShowNativeDialog() instead of having
it if-zeroed.
Then remove LIBO_HEADLESS ifdefery from unx/generic/plugadapt/salplug.cxx
which we are not building anymore.

statements like
  Dim AppEnd As Integer
will generate compiler errors because Append is a special symbol/keyword in libreoffice basic. This restriction though is too strict because 'Append' is only such a keyword when used within the 'Open' statement ( where it refers to one of the possible values for a paramater ).

I.e. BASIC stuff for iOS and database connectivity stuff when using
--disable-database-connectivity. All of this quite experimental so
far, using the latter will break your build.

mmeeks suggests we don't want setIniFilename(), who am i to disagree? :)

tml reminds us that use a generic and potentially clash-prone word
like HEADLESS as preprocessor defintion is pretty lame.
He suggests to put it under the already used LIBO namespace.
To sum it up let's do a s/HEADLESS/LIBO_HEADLESS/g.

This reverts commit 8c674283, which had been
obsoleted by e69b8a75 "disabled officecfg
unittest due to dependencies problems."