7 * Getting something that works in C and CPP for an arg that may or may
8 * not be defined is tricky. Here, if we have "#define CONFIG_BOOGER 1"
9 * we match on the placeholder define, insert the "0," for arg1 and generate
10 * the triplet (0, 1, 0). Then the last step cherry picks the 2nd arg (a one).
11 * When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when
12 * the last step cherry picks the 2nd arg, we get a zero.
14 #define __ARG_PLACEHOLDER_1 0,
15 #define config_enabled(cfg) _config_enabled(cfg)
16 #define _config_enabled(value) __config_enabled(__ARG_PLACEHOLDER_##value)
17 #define __config_enabled(arg1_or_junk) ___config_enabled(arg1_or_junk 1, 0, 0)
18 #define ___config_enabled(__ignored, val, ...) val
20 #define CONFIG(option) config_enabled(CONFIG_##option)