[cstr_fixed.h] Moving include to top of file

include/toolbox/cstr_fixed.h

@@ -1,12 +1,12 @@
 #ifndef TOOLBOX_CSTR_FIXED_H
 #define TOOLBOX_CSTR_FIXED_H
 
+#include <stddef.h>
+
 #ifndef TOOLBOX_CSTR_FIXED_MAX_SIZE
 #define TOOLBOX_CSTR_FIXED_MAX_SIZE ((size_t) 255L)
 #endif
 
-#include <stddef.h>
-
 struct cstr_fixed {
 	size_t size;
 	char data[TOOLBOX_CSTR_FIXED_MAX_SIZE];