Add common I_GetSysName function

Replaces the OS defines in Command_Version_f() with a common function to fetch the system name the game is currently running on.

src/dummy/i_system.c

@@ -206,5 +206,10 @@ void I_GetCursorPosition(INT32 *x, INT32 *y)
 	(void)y;
 }
 
+const char *I_GetSysName(void)
+{
+	return NULL;
+}
+
 #include "../sdl/dosstr.c"
 

src/i_system.h

@@ -335,4 +335,8 @@ void I_GetCursorPosition(INT32 *x, INT32 *y);
 */
 void I_SetMouseGrab(boolean grab);
 
+/** \brief Returns the system name.
+*/
+const char *I_GetSysName(void);
+
 #endif

src/netcode/d_netcmd.c

@@ -3812,18 +3812,7 @@ static void Command_Version_f(void)
 #endif
 
 	// OS
-	// Would be nice to use SDL_GetPlatform for this
-#if defined (_WIN32) || defined (_WIN64)
-	CONS_Printf("Windows ");
-#elif defined(__linux__)
-	CONS_Printf("Linux ");
-#elif defined(MACOSX)
-	CONS_Printf("macOS ");
-#elif defined(UNIXCOMMON)
-	CONS_Printf("Unix (Common) ");
-#else
-	CONS_Printf("Other OS ");
-#endif
+	CONS_Printf("%s ", I_GetSysName());
 
 	// Bitness
 	if (sizeof(void*) == 4)

src/sdl/i_system.c

@@ -3256,4 +3256,10 @@ const CPUInfoFlags *I_CPUInfo(void)
 
 // note CPUAFFINITY code used to reside here
 void I_RegisterSysCommands(void) {}
+
+const char *I_GetSysName(void)
+{
+	return SDL_GetPlatform();
+}
+
 #endif