BUG #16403: set_bit function does not have expected effect

The following bug has been logged on the website:

Bug reference: 16403
Logged by: Alex Movitz
Email address: amovitz(at)bncpu(dot)com
PostgreSQL version: 11.0
Operating system: Linux
Description:

Input:
SELECT set_bit('\x00000000'::bytea, 0, 1);
Expected Output:
'\x00000001' or '\x80000000'
Actual Output:
'\x01000000'

Input:
SELECT set_bit('\x00000000'::bytea, 8, 1);
Expected Output:
'\x00000100' or '\x00800000'
Actual Output:
'\x00010000'

Issue:
set_bit function changes the right-most bit of the byte, but with
little-endian byte order. This is confusing to any use case where setting a
bit in a BYTEA in a specific position. To iterate through the bits within
the BYTEA, one must have nested loops which set bits within byte boundaries.