Rename I_StartupKeyboard to I_RegisterSignals and call it in a sane place

src/d_main.c

@@ -613,9 +613,6 @@ void D_SRB2Loop(void)
 
 	// Pushing of + parameters is now done back in D_SRB2Main, not here.
 
-	CONS_Printf("I_StartupKeyboard()...\n");
-	I_StartupKeyboard();
-
 #ifdef _WINDOWS
 	CONS_Printf("I_StartupMouse()...\n");
 	I_DoStartupMouse();

src/i_system.h

@@ -226,10 +226,6 @@ void I_StartupMouse(void);
 */
 void I_StartupMouse2(void);
 
-/**	\brief keyboard startup, shutdown, handler
-*/
-void I_StartupKeyboard(void);
-
 /**	\brief  setup timer irq and user timer routine.
 */
 void I_StartupTimer(void);

src/sdl/i_system.c

@@ -692,7 +692,7 @@ static inline void I_ShutdownConsole(void){}
 //
 // StartupKeyboard
 //
-void I_StartupKeyboard (void)
+void I_RegisterSignals (void)
 {
 #ifdef SIGINT
 	signal(SIGINT , quit_handler);
@@ -3111,6 +3111,7 @@ INT32 I_StartupSystem(void)
 #ifdef NEWSIGNALHANDLER
 	I_Fork();
 #endif
+	I_RegisterSignals();
 	I_OutputMsg("Compiled for SDL version: %d.%d.%d\n",
 	 SDLcompiled.major, SDLcompiled.minor, SDLcompiled.patch);
 	I_OutputMsg("Linked with SDL version: %d.%d.%d\n",