Correctly handle indirect symbols.

pkgutil.pas:
  * export_unit: don't export indirect symbols
  * createimportlibfromexternals: if an indirect symbols is unresolved we import the non-indirect symbol
  * createimportlibfromexternals.findpackagewithsym: we only need the symbols name to find the symbol, not the complete tasmsymbol

git-svn-id: http://svn.freepascal.org/svn/fpc/branches/svenbarth@28906 3ad0048d-3df7-0310-abae-a5850022a9f2