I went with a basic -O2, FWIW

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I've never handled fat binaries manually, I'll see what I can come up with, if no one beats me to it (is that even doable w/ a 10.10 SDK?)

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EDIT: Yes it is, and apparently as simple as passing -arch i386 -arch x86_64 to the compiler & linker

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Code:
gcc -pipe -O2 -fomit-frame-pointer -mmacosx-version-min=10.6 -arch i386 -arch x86_64 -Wall -o patch32lsb patch32lsb.c