Use OpenMP on Windows too (#406)

It seems like currently pytorch links to both libiomp5md and vcomp.

Author: isuruf

recipe/bld.bat

@@ -74,8 +74,7 @@ set "USE_LITE_PROTO=ON"
 SET "USE_ITT=0"
 SET "USE_NUMA=0"
 
-@REM TODO(baszalmstra): There are linker errors because of mixing Intel OpenMP (iomp) and Microsoft OpenMP (vcomp)
-set "USE_OPENMP=OFF"
+set "USE_OPENMP=ON"
 
 @REM Use our Pybind11, Eigen, sleef
 set USE_SYSTEM_EIGEN_INSTALL=1

recipe/meta.yaml

@@ -1,6 +1,6 @@
 # if you wish to build release candidate number X, append the version string with ".rcX"
 {% set version = "2.7.1" %}
-{% set build = 3 %}
+{% set build = 4 %}
 
 # Use a higher build number for the CUDA variant, to ensure that it's
 # preferred by conda's solver, and it's preferentially