'=' cannot be handled in the same manner as other "critical" characters
as no amount of backslashes will escape it. Use a variable instead.
The documentation for nmake suggests that '=' in file names is not among
the "Special Characters in a Makefile". Therefore, we assume nmake can
handle it and don't escape it.
Fixes: QTBUG-67262
Change-Id: Ib60f808d7d4e981c98f7d8bf2075d55b2b7f3b7d
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>
Reviewed-by: Michael Brasser <michael.brasser@live.com>
5ed471a80a