How to use Windows US-Intl keyboard layout on a Mac?
You can make the Alt/Option level of Apple's US International PC behave like the version you are used to by creating a custom keyboard layout with the app Ukelele.

For reference the Alt/Option behavior of Windows US International is here.

Note that on a Mac both left and right alt/option keys normally do the same thing, i.e. create special characters.

PS  If in fact your right alt key does not produce any characters at all, then something is broken with your keyboard or software.

An experimental keyboard that tries to conform to the Windows version can be found here.

Note:  If you want something like one of the Linux versions of "US International" which have a dozen or more dead keys for making a huge number of diacritic and other characters, then the Apple equivalent is ABC Extended, whose layout is however quite different.  For that see this earlier question.