Add stringify macro to utils

Add macros for stringifying either the name of a macro or its value.  In
keeping with making our utils/ sort of look like kernel code, we use the
kernel stringify names.

Signed-off-by: Zach Brown <zab@versity.com>

utils/src/util.h

@@ -114,4 +114,7 @@ static inline int memcmp_lens(const void *a, int a_len,
 int get_path(char *path, int flags);
 int read_block(int fd, u64 blkno, int shift, void **ret_val);
 
+#define __stringify_1(x) #x
+#define __stringify(x) __stringify_1(x)
+
 #endif