Add support for SDL3 joystick input driver

Made possible by EIREXE, xsellier and the SDL team.

This commit includes statically linked SDL3 for Windows, Linux and macOS.
The vendored copy of SDL3 was setup to only build the required subsystems
for gamepad/joystick support, with some patches to be able to make it as
minimal as possible and reduce the impact on binary size and code size.

Co-authored-by: Álex Román Núñez <eirexe123@gmail.com>
Co-authored-by: Xavier Sellier <xsellier@gmail.com>
Co-authored-by: Rémi Verschelde <rverschelde@gmail.com>

thirdparty/sdl/libm/s_fabs.c

@@ -0,0 +1,30 @@
+#include "SDL_internal.h"
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+/*
+ * fabs(x) returns the absolute value of x.
+ */
+
+/*#include <features.h>*/
+/* Prevent math.h from defining a colliding inline */
+#undef __USE_EXTERN_INLINES
+#include "math_libm.h"
+#include "math_private.h"
+
+double fabs(double x)
+{
+	u_int32_t high;
+	GET_HIGH_WORD(high,x);
+	SET_HIGH_WORD(x,high&0x7fffffff);
+        return x;
+}
+libm_hidden_def(fabs)