Yes, saying that you were adapting for a Canon
dSLR, when you meant an EOS M mirrorless camera was not being particularly clear...or accurate.
Yes, you can then easily use the FD lenses with a ring adapter, and that simplifies things, and may make it more worthwhile. However, you now have a different problem--tiny mirrorless camera and
big honking SLR lens. Forget sticking that combo in your pocket.
And it might be a bit long for general walkaround usage on APS-C. That's up to you and what you were planning on shooting with it.
Also consider, that your 50/1.8 FD lens may be $25, but you may also need to blow $40 on a good chipped adapter ring. And then maybe $100 if it turns out one of the shutter leaves is stuck with old grease to get the lens serviced and cleaned. And you still won't have autofocus or aperture control from the body. Put that up against the $120 you'd pay for a brand spankin' new EF-M 22mm f/2 STM pancake lens that's designed to work with the EOS M, and you need to be a special kind of stubborn to still want the FD lens.
Maybe you're that kind of stubborn (I am). Just understand that what you're saving in pricetag is paid for in PITAness of using the lens.