Core: Purge WITH_IMGUI define

src/core/mdec.cpp

@@ -3,11 +3,9 @@
 #include "common/state_wrapper.h"
 #include "cpu_core.h"
 #include "dma.h"
+#include "imgui.h"
 #include "interrupt_controller.h"
 #include "system.h"
-#ifdef WITH_IMGUI
-#include "imgui.h"
-#endif
 Log_SetChannel(MDEC);
 
 MDEC g_mdec;
@@ -724,7 +722,6 @@ void MDEC::HandleSetScaleCommand()
 
 void MDEC::DrawDebugStateWindow()
 {
-#ifdef WITH_IMGUI
   const float framebuffer_scale = ImGui::GetIO().DisplayFramebufferScale.x;
 
   ImGui::SetNextWindowSize(ImVec2(300.0f * framebuffer_scale, 350.0f * framebuffer_scale), ImGuiCond_FirstUseEver);
@@ -762,5 +759,4 @@ void MDEC::DrawDebugStateWindow()
   }
 
   ImGui::End();
-#endif
 }