Add unpack_bit_str_hex_as_inx macro to pack.h.

RPCs will switch to using bit_str_hex for serialization from bit_fmt,
but receivers still need to access this as a inx formatted array for now.
Collapse this into one macro rather than repeating a bunch of times.

Note that this would be better performing if consolidated into a single
function rather than using unpack_bit_str_hex then bitstr2inx to convert;
although this is a client-side function and less important than avoiding
performance and throughput issues within slurmctld.

src/common/pack.h

@@ -328,6 +328,15 @@ int	unpackmem_array(char *valp, uint32_t size_valp, Buf buffer);
 		*bitmap = NULL;						\
 } while (0)
 
+/* note: this would be faster if collapsed into a single function
+ * rather than a combination of unpack_bit_str_hex and bitstr2inx */
+#define unpack_bit_str_hex_as_inx(inx, buf) do {	\
+	bitstr_t *b = NULL;				\
+	unpack_bit_str_hex(&b, buf);			\
+	*inx = bitstr2inx(b);				\
+	bit_free(b);					\
+} while (0)
+
 #define unpackstr_ptr		                        \
         unpackmem_ptr