Added IMGUI_DISABLE_SSE (#4250, #4091)

imconfig.h

@@ -45,6 +45,7 @@
 //#define IMGUI_DISABLE_FILE_FUNCTIONS                      // Don't implement ImFileOpen/ImFileClose/ImFileRead/ImFileWrite and ImFileHandle at all (replace them with dummies)
 //#define IMGUI_DISABLE_DEFAULT_FILE_FUNCTIONS              // Don't implement ImFileOpen/ImFileClose/ImFileRead/ImFileWrite and ImFileHandle so you can implement them yourself if you don't want to link with fopen/fclose/fread/fwrite. This will also disable the LogToTTY() function.
 //#define IMGUI_DISABLE_DEFAULT_ALLOCATORS                  // Don't implement default allocators calling malloc()/free() to avoid linking with them. You will need to call ImGui::SetAllocatorFunctions().
+//#define IMGUI_DISABLE_SSE                                 // Disable use of SSE intrinsics even if available
 
 //---- Include imgui_user.h at the end of imgui.h as a convenience
 //#define IMGUI_INCLUDE_IMGUI_USER_H

imgui_internal.h

@@ -52,7 +52,7 @@ Index of this file:
 #include <limits.h>     // INT_MIN, INT_MAX
 
 // Enable SSE intrinsics if available
-#if defined __SSE__ || defined __x86_64__ || defined _M_X64
+#if (defined __SSE__ || defined __x86_64__ || defined _M_X64) && !defined(IMGUI_DISABLE_SSE)
 #define IMGUI_ENABLE_SSE
 #include <immintrin.h>
 #endif