Composer doesn\'t run correctly in Cygwin if you try to install it \"globally\".
Putting composer.phar into /usr/local/bin/composer, then trying to run it will result in
I was having this issue. Most of the responses were over my head but I fixed it with no problems.
Step 1) Reinstall Composer globally as per https://getcomposer.org/download/
Step 2) Leave it alone. All the special stuff you want to do, don't do that.
Step 3) Download the latest setup-xxx.exe from https://cygwin.com/
Step 4) Click it with your mouse.
NOTE: During step 5 you will feel a sudden urge to read instructions, browse the web for info and start checking little boxes on the menu. Don't do that.
Step 5) Click 'next' until it stops asking. It will look at your existing settings, fix things up and add any missing dependencies.
This worked for me.