Fixed cmake script so that nvcc gets the correct compiler options sent to it

(in particular on mac os x, where this flag needs to be set this way for it to
work in some cases).

dlib/CMakeLists.txt

@@ -511,7 +511,7 @@ if (NOT TARGET dlib)
             # -std=c++11 option if you let it propagate it to nvcc in some
             # cases.  So instead we disable this and manually include
             # things from CMAKE_CXX_FLAGS in the CUDA_NVCC_FLAGS list below.
-            if (!MSVC)
+            if (NOT MSVC)
                set(CUDA_PROPAGATE_HOST_FLAGS OFF)
             endif()