When using visual studio, made cmake only show the supported SSE options.

dlib/cmake

@@ -13,7 +13,7 @@ if (NOT TARGET dlib)
     endif()
 
     # Setup some options to allow a user to enable SSE and AVX instruction use.  
-    if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+    if (CMAKE_COMPILER_IS_GNUCXX OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
         option(USE_SSE2_INSTRUCTIONS "Compile your program with SSE2 instructions" OFF)
         option(USE_SSE4_INSTRUCTIONS "Compile your program with SSE4 instructions" OFF)
         option(USE_AVX_INSTRUCTIONS  "Compile your program with AVX instructions"  OFF)
@@ -24,11 +24,17 @@ if (NOT TARGET dlib)
         elseif(USE_SSE2_INSTRUCTIONS)
             add_definitions(-msse2)
         endif()
-    elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC") # else if using Visual Studio 
+    elseif (MSVC OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC") # else if using Visual Studio 
         # Use SSE2 by default when using Visual Studio.
         option(USE_SSE2_INSTRUCTIONS "Compile your program with SSE2 instructions" ON)
+        # Visual Studio 2005 didn't support SSE4 
+        if (NOT MSVC80)
             option(USE_SSE4_INSTRUCTIONS "Compile your program with SSE4 instructions" OFF)
+        endif()
+        # Visual Studio 2005 and 2008 didn't support AVX
+        if (NOT MSVC80 AND NOT MSVC90)
             option(USE_AVX_INSTRUCTIONS  "Compile your program with AVX instructions"  OFF)
+        endif() 
         include(CheckTypeSize)
         check_type_size( "void*" SIZE_OF_VOID_PTR)
         if(USE_AVX_INSTRUCTIONS)