Rename 'Standard Gaming Platform' to 'sgp' (#246)

* rename 'Standard Gaming Platform' to 'sgp'

* Adapt CMakeLists.txt files to renamed SGP directory

* Lowercase it

sgp/mousesystem_macros.h

@@ -0,0 +1,40 @@
+//=================================================================================================
+//	MouseSystem_Macros.h
+//
+//	Macro definitions for the "mousesystem" mouse region handler.
+//
+//	This file is included by "mousesystem.h" or can be included by itself.
+//
+//	Written by Bret Rowdon. Jan 30 '97
+//=================================================================================================
+
+#ifndef _MOUSE_SYSTEM_MACROS_H_
+#define _MOUSE_SYSTEM_MACROS_H_
+
+// Special macro hook for the mouse handler. Allows a call to a secondary mouse handler.
+// Define the label _MOUSE_SYSTEM_HOOK_ to activate. Undef it to deactivate.
+//
+// The actual function prototype is shown below
+
+#define _MOUSE_SYSTEM_HOOK_
+
+#ifdef _MOUSE_SYSTEM_HOOK_
+	#define MouseSystemHook(t,x,y,l,r)		MSYS_SGP_Mouse_Handler_Hook(t,x,y,l,r)
+#else
+	#define MouseSystemHook(t,x,y,l,r)
+#endif
+
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Special prototype for mouse handler hook
+extern void MSYS_SGP_Mouse_Handler_Hook(UINT16 Type, UINT16 Xcoord, UINT16 Ycoord, BOOLEAN LeftButton, BOOLEAN RightButton);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif