[CMake] VS2012 builds using v3.1.0 are a lot slower than v2.8.12

[Yves Frederix]

Hi,

>> 3.1.0:
>>         ALL                 Crypto          Crypto_s        Crypto_test
>> real    0m38.211s           0m14.023s       0m7.003s        0m14.691s
>>
>> 2.8.12:
>>         ALL                 Crypto          Crypto_s        Crypto_test
>> real    0m27.230s           0m17.110s       0m10.231s       0m18.618s
>
> Interesting, thanks for the timings.
>
>> This made me wonder if it maybe had to do with default settings for
>> parallelization in the builds. So I tried, and if I explicitly "set
>> CL=/MP" for the 3.1.0 build, build time reduces from 38 seconds to 24
>> seconds which is what I would expect. Could this be the cause and was
>> there a change in default settings?
>
> I don't think such a change was made intentionally.  To help narrow
> it down, could you please do the timings for CMake 3.0.2 as well?

The behavior seems to be the same for 3.0.2:

3.0.2:
          ALL                 Crypto          Crypto_s        Crypto_test
real    0m38.756s           0m14.113s       0m7.150s        0m15.106s


Regards,
Yves