yes, the game needs those missing libraries to run correctly, consistently.
my advice, which i take no responsibility for;p would be to:
1. install xcode
2. install wineskin
3.
download SteamInstaller.msi
4. create a wrapper (use wine 1.4.1NoXInput2)
5. use winetricks,winecfg and advanced options to tweak the wrapper (steps 3 & 4 in the guide)
6. install the steam client:
under Wineskin Advanced=>Configuration, click Install Software
choose setup.exe and install Steam client from .msi file
go to Configuration (look at the picture) chose correct exe path and set flag "-no-dwrite". click the Test Run button
steam will auto-update, just like every time you connect to steam
steam may freeze, force quit if the updater seems to hang and relaunch
eventually i was able to enter my credentials, i got a text message on my phone to verify the new "machine"
from here i was able to click around pretty normally, look at my purchases, etc.
=============== after this point i have not tried anything that follows. good luck!
7. install civ version whatever. i think on steam there is civ4 vanilla for $20, and complete is $30 neither requires an update, sfaik
8. delete the "-no-dwrite" flag under Configuration and change the Windows EXE to something like:
c:/ProgramFiles (x86)/Steam/SteamApps/common/.../.../Civ4BeyondSword.exe
9. at this point, civ should be installed and running. go back to step 6 in the guide, skipping the bit about running the updater.
let me know if this works, i have no idea if steam's DRM is going to be a problem, but from my experience it works as advertised.
that is to say, you only need to log in to download your games, you don't have to be online to play them.
it would be kind of neat if the steam achievements would still work with this setup.
one last thing, you can make a batch.bat file to launch two programs at the same time in wine, so if steam has to be running, this would be the solution. also, the steam client throws up GameOverlayRenderer.dll errors, so don't run it if you don't have to.