Invoke-NMake helper temporarily clears MAKE flags, such as
MAKEFLAGS='-j8', to prevent errors from GNU-style flags and to reduce
flakiness with NMAKE.
The helper is used to build zlib and to prevent:
error U1065: invalid option '-'
Pick-to: 6.9 6.8 6.5
Task-number: QTQAINFRA-7363
Change-Id: Ia80216677eba6fd8f8364741b6999e6155d678ab
Reviewed-by: Tero Heikkinen <tero.heikkinen@qt.io>
(cherry picked from commit 0f3d085101)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
