Since commit 059172c6 precompiled headers did not work anymore on
macOS, because the ${QMAKE_PCH_ARCH} string was suddenly appearing in
locations where it was not replaced with the actual architecture, e.g.
the directory where the PCH files are written.
Fix this by replacing the whole file path and not just portions of it.
Fixes: QTBUG-79694
Change-Id: I925d4ee8980a0de3205a0e387a516a5c6f8cfa4b
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Reviewed-by: BogDan Vatra <bogdan@kdab.com>
Reviewed-by: Kai Koehne <kai.koehne@qt.io>
52c8e9dc99