Discrepancy between 'display usage' in command line and actual behavior for --config option

Description

On PC, using the command line, the 'display usage' wrongfully states the syntax for --config is --config=FILE
the = does not work (at least in a PC environment) and for the option to work properly we need to use a space separator. (--config FILE, like --log-file FILE)
Maybe just change the documentation (in retroarch.c) to remove the = will be a reasonable fix
Other options may also be affected by the same discrepancy between documentation and actual behavior.

Expected behavior

I am expecting the displayed usage for option --config to be right.

Actual behavior

retroarch.exe --config=retroarch2.cfg just displays the list of options
retroarch.exe -c=retroarch2.cfg starts retroarch properly, but creates a file actually named =retroarch2.cfg (with the = )

Steps to reproduce the bug

1. run retroarch.exe -h -> shows -c, --config=FILE Path for config file.
2. run retroarch.exe --config=retroarch2.cfg -> does not work
3. run 2. run retroarch.exe -c=retroarch2.cfg -> creates a file named =retroarch2.cfg

Version/Commit

1.8.2

• RetroArch: [version/commit]

Environment information

• OS: Windows 10 (1909)

Open retroarch.c and locate the usage text for --config; compare its documented syntax with the reported behavior for --config=FILE and -c=FILE on Windows. Check whether other option usage strings have the same discrepancy, then verify that the displayed usage and --config invocation agree.