fix Windows build

[Be-ing]

Looks like #1377 broke the Windows build. We urgently need reliable CI!!

[Be-ing]

Okay, the compile error with ratecontrol.cpp is fixed. The build is failing for an unrelated reason which has been affecting lots of AppVeyor builds seemingly randomly:
LINK : fatal error LNK1181: cannot open input file 'vamp-sdk.lib'

[sblaisot]

no, the build is failing because of

[CXX] src\preferences\dialog\dlgprefdeck.cpp
dlgprefdeck.cpp
src\preferences\dialog\dlgprefdeck.cpp(459): error C2440: 'static_cast': cannot convert from 'double' to 'TrackTime::DisplayMode'
src\preferences\dialog\dlgprefdeck.cpp(459): note: Conversions between enumeration and floating point values are no longer allowed
scons: *** [win64_build\preferences\dialog\dlgprefdeck.obj] Error 2
scons: building terminated because of errors.

line 7274-7279 of the log

[Be-ing]

Ack, thanks for pointing that out.

[sblaisot]

you should be interested in #1440

[Be-ing]

Okay, AppVeyor build is working with this. EngineBufferE2ETest.KeylockReverseTest is failing, which I have already fixed in #1254