symbols: add GroupInfo

GroupInfo keeps all of the info for a specific group in one struct.
This is the old array-of-structures vs. structure-of-arrays, but in this
case readability wins. It would also help with lifting the
XkbNumKbdGroups limit, because we only have to worry about one array
(instead of 6).

Signed-off-by: Ran Benita <ran234@gmail.com>

src/utils.h

@@ -79,7 +79,9 @@ strnull(const char *s)
 }
 
 #define MIN(a, b) ((a) < (b) ? (a) : (b))
+#define MIN3(a, b, c) MIN(MIN((a), (b)), (c))
 #define MAX(a, b) ((a) > (b) ? (a) : (b))
+#define MAX3(a, b, c) MAX(MAX((a), (b)), (c))
 
 /* Compiler Attributes */