Revert "Add executable suffix to compiler"

* Refers to target OS instead of host OS
* Breaks Creator integration (which uses full path including the suffix)

This reverts commit cbabc2a263fafdc0df2b428ace563b6033b5d041

Change-Id: I419ef5b144790208587c0b694a9b5bf2e1b2dacb
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>