sys: util: Accept empty FOR_EACH

The ## part of ##__VA_ARGS__ in the Z_FOR_EACH_ENGINE macro technically
breaks the invocation of empty FOR_EACH sequences, as the empty
__VA_ARGS__ gets squashed with in the invocation of Z_FOR_LOOP_1() in
Z_FOR_LOOP_2(), which makes the macro only pass 4 arguments to
Z_FOR_LOOP_1.

This breaks IntelliSense in Microsoft's C/C++ extension for VS Code,
which is strict about the amount of arguments you can pass to a variadic
macro.

Signed-off-by: Krzysztof Chruściński <[email protected]>
Signed-off-by: Trond Einar Snekvik <[email protected]>

Author: trond-snekvik

include/zephyr/sys/util_loops.h

@@ -408,7 +408,7 @@
 		Z_FOR_LOOP_3, \
 		Z_FOR_LOOP_2, \
 		Z_FOR_LOOP_1, \
-		Z_FOR_LOOP_0)(x, sep, fixed_arg0, fixed_arg1, ##__VA_ARGS__)
+		Z_FOR_LOOP_0)(x, sep, fixed_arg0, fixed_arg1, __VA_ARGS__)
 
 #define Z_GET_ARG_1(_0, ...) _0