BUG #15856: The program "postgres" was found by "initdb" but was not the same version as initdb.

The following bug has been logged on the website:

Bug reference: 15856
Logged by: Luc
Email address: iq2luc(at)gmail(dot)com
PostgreSQL version: 11.3
Operating system: Microsoft Windows [Version 10.0.17763.557]
Description:

Cluster initialization via initdb fails on 11.3 while on previous versions
(tested 10.8 and 9.6.13) works OK with exactly the same command line.

Testing procedure (exactly the same for each version):
1. Download binary files using official download link:
https://www.enterprisedb.com/download-postgresql-binaries
2. Unpack to a local directory
3. Run the console command: initdb.exe -D c:\test\db -E UTF8
--locale=English_Europe.1250

Expected result: database cluster properly initialized on 11.3, 10.8 and
9.6.13.
Actual result: database cluster initialization fails on 11.3 but works on
10.8 and 9.6.13 (see console outputs below).

Binaries used:
* 11.3 -> http://sbp.enterprisedb.com/getfile.jsp?fileid=11625
* 10.8 -> http://sbp.enterprisedb.com/getfile.jsp?fileid=11635
* 9.6.13 -> http://sbp.enterprisedb.com/getfile.jsp?fileid=11647

Console output on 11.3
==================

c:\test\pg11> bin\initdb.exe -D c:\test\db -E UTF8
--locale=English_Europe.1250
The program "postgres" was found by "c:/test/pg11/bin/initdb.exe"
but was not the same version as initdb.
Check your installation.

c:\test\pg11> bin\initdb.exe -V
initdb (PostgreSQL) 11.3

c:\test\pg11> bin\postgres.exe -V
postgres (PostgreSQL) 11.3

Console output on 10.8 (similar on 9.6.13)
================================

c:\test\pg10> bin\initdb.exe -D c:\test\db -E UTF8
--locale=English_Europe.1250
The files belonging to this database system will be owned by user "Luc".
This user must also own the server process.

The database cluster will be initialized with locale
"English_Europe.1250".
The default text search configuration will be set to "english".

Data page checksums are disabled.

fixing permissions on existing directory c:/test/db ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 128MB
selecting dynamic shared memory implementation ... windows
creating configuration files ... ok
running bootstrap script ... ok
performing post-bootstrap initialization ... ok
syncing data to disk ... ok

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the option -A, or
--auth-local and --auth-host, the next time you run initdb.

Success. You can now start the database server using:

bin/pg_ctl -D ^"c^:^\test^\db^" -l logfile start