engine: fix some const qualifier lose and pointer-to-int casts

engine/client/cl_main.c

@@ -2535,7 +2535,7 @@ CL_ServerCommand
 send command to a server
 ====================
 */
-void CL_ServerCommand( qboolean reliable, char *fmt, ... )
+void CL_ServerCommand( qboolean reliable, const char *fmt, ... )
 {
 	char		string[MAX_SYSPATH];
 	va_list		argptr;

engine/client/console.c

@@ -990,13 +990,12 @@ void GAME_EXPORT Con_DrawStringLen( const char *pText, int *length, int *height
 {
 	int	curLength = 0;
 
-	if( !con.curFont ) return;
-
-	if( height ) *height = con.curFont->charHeight;
 	if( !length ) return;
-
 	*length = 0;
 
+	if( !con.curFont ) return;
+	if( height ) *height = con.curFont->charHeight;
+
 	while( *pText )
 	{
 		byte	c = *pText;

engine/client/keys.c

@@ -29,7 +29,7 @@ typedef struct
 
 typedef struct keyname_s
 {
-	char		*name;	// key name
+	const char	*name;	// key name
 	int		keynum;	// key number
 	const char	*binding;	// default bind
 } keyname_t;

engine/client/s_main.c

@@ -1773,7 +1773,7 @@ void S_Music_f( void )
 	else if( c == 2 )
 	{
 		string	intro, main, track;
-		char	*ext[] = { "mp3", "wav" };
+		const char	*ext[] = { "mp3", "wav" };
 		int	i;
 
 		Q_strncpy( track, Cmd_Argv( 1 ), sizeof( track ));