[Groff] Groff command-line argument strangeness

[Koz Ross]

I've just discovered groff, and am quite impressed! However, for some reason, 
I'm having an odd issue. I have a folder called 'src' where I plan to store 
chapters of my book, and I want to add it to the search path for stuff to 
include into the final document. I give groff the following command to format:

groff -b -Ffont -Isrc -Mmacro -ms -U -wall -dpaper=a4 -Tpdf a-stranger-world.ms 
> a-stranger-world.pdf

However, when I do this, groff gives the following warnings:

Unknown option: I
Unknown option: r
Unknown option: c

Have I done something wrong, and if so, what?
-- 
Koz Ross <address@hidden>
www.retro-freedom.nz
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