fix more cases of mkdir_asstring() argument overquoting

Change-Id: I7dd4024fb6fceb47431b626b586a471b74789cdc
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Fix mkdir command in Windows shell for paths with forward-slashes

In particular this triggers in some cases of package building
where we are using a Qt version which for some reason has
forward slashes in its install prefix. Any mkdir command
run with this Qt build will fail because only backslashes are
recognized as path separators.

Task-number: QTBUG-34886
Change-Id: I2f957c6d348852ec555a67a35ae39921523b7b3e
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
install pdb files for dlltarget

Task-number: QTBUG-31129
Change-Id: I49ef3472d12b291999b4194b014b200df4b0f22d
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>