at least the mingw version we use now interprets the sequence \# as a
literal hashmark, which completely defeats the previous hack.
the new hack escapes the backslash with another backslash, which appears
to work. however, make does *not* remove the additional backslash, so
the result is a bit ugly.
Change-Id: I591a2be443880b162094d04e5a5e624216b59311
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>