Cleanup: quiet unused variable warnings in CMake

OpenMP_LIBRARIES was used when it wasn't defined.

build_files/cmake/Modules/GTestTesting.cmake

@@ -72,7 +72,7 @@ macro(BLENDER_SRC_GTEST_EX)
     if(DEFINED PTHREADS_LIBRARIES) # Needed for GLOG.
       target_link_libraries(${TARGET_NAME} PRIVATE ${PTHREADS_LIBRARIES})
     endif()
-    if(WITH_OPENMP_STATIC)
+    if(WITH_OPENMP AND WITH_OPENMP_STATIC)
       target_link_libraries(${TARGET_NAME} PRIVATE ${OpenMP_LIBRARIES})
     endif()
     if(UNIX AND NOT APPLE)

intern/opensubdiv/CMakeLists.txt

@@ -76,7 +76,7 @@ if(WITH_OPENSUBDIV)
     ${OPENSUBDIV_LIBRARIES}
   )
 
-  if(WITH_OPENMP_STATIC)
+  if(WITH_OPENMP AND WITH_OPENMP_STATIC)
     list(APPEND LIB
       ${OpenMP_LIBRARIES}
     )